Decide, decision, decisive, decisively. Learn how one word becomes four, with noun, verb, adjective and adverb forms, suffix rules and practice for essays and exams.
If you know the word decide, you already know decision, decisive and decisively. This group is a word family: a base word and the other words formed from it, each with a different part of speech. Learning words in families is one of the fastest ways to build your vocabulary, because one new word gives you four or five.
This guide explains what word families are, how suffixes show the part of speech, and the spelling changes that happen when words change form. Its main part gives 178 word families in five themed tables, each in four columns: noun, verb, adjective and adverb. It also covers people nouns, adverbs with different meanings, words formed from the same base with different meanings, fifteen practice sentences with answers, ways to use word families to improve essays, common mistakes, key points, ten practice questions and a teacher activity.
It builds on Parts of Speech and connects with Root Words, Prefixes and Suffixes, Degrees of Adjectives, Collocations in English and Commonly Misspelled Words. Spelling in this guide follows British English.
A word family is a group of words that share the same base and are related in meaning, but have different forms and different jobs in a sentence.
| Part of speech | Form | Job in a sentence | Example sentence |
|---|---|---|---|
| Noun | decision | names a thing or idea | It was a wise decision. |
| Verb | decide | shows an action | We decide tomorrow. |
| Adjective | decisive | describes a noun | She is a decisive leader. |
| Adverb | decisively | describes a verb | She acted decisively. |
Not every family has all four forms. Some have no verb (happiness, happy, happily) and some have no adverb (pollution, pollute, polluted). In the tables, a dash (—) means that no common form exists.
The ending of a word is often the best clue to its part of speech.
| Part of speech | Common endings | Examples |
|---|---|---|
| Noun | -tion, -sion, -ment, -ness, -ity, -ance, -ence, -ism, -ship, -hood | decision, movement, kindness, ability, importance |
| Verb | -ise (-ize), -ify, -en, -ate | realise, simplify, strengthen, activate |
| Adjective | -ful, -less, -ous, -al, -ive, -ic, -able, -ible, -y, -ent, -ant | helpful, famous, national, active, rainy |
| Adverb | -ly, -ally, -ily, -ably, -ibly | quickly, basically, happily, reliably |
| Change | Examples |
|---|---|
| Drop silent e before a vowel ending | create → creation, decide → decision, admire → admirable |
| Change y to i before an ending | happy → happiness, happily; beauty → beautiful |
| Add -ally to words ending in -ic | basic → basically, economic → economically (exception: public → publicly) |
| -le becomes -ly | possible → possibly, simple → simply |
| -ue becomes -uly | true → truly, due → duly |
| Verb ends in -ify | simple → simplify, pure → purify, clear → clarify |
| The stress can move | PHOtograph, phoTOGraphy, photoGRAPHic |
| The root may change | decide → decision, explain → explanation, compete → competition |
| Noun | Verb | Adjective | Adverb |
|---|---|---|---|
| decision | decide | decisive | decisively |
| imagination | imagine | imaginative | imaginatively |
| creation | create | creative | creatively |
| description | describe | descriptive | descriptively |
| comparison | compare | comparative | comparatively |
| conclusion | conclude | conclusive | conclusively |
| confusion | confuse | confusing | confusingly |
| education | educate | educational | educationally |
| invention | invent | inventive | inventively |
| information | inform | informative | informatively |
| persuasion | persuade | persuasive | persuasively |
| prediction | predict | predictable | predictably |
| explanation | explain | explanatory | — |
| observation | observe | observant | observantly |
| communication | communicate | communicative | communicatively |
| expression | express | expressive | expressively |
| impression | impress | impressive | impressively |
| suspicion | suspect | suspicious | suspiciously |
| intention | intend | intentional | intentionally |
| attention | attend | attentive | attentively |
| knowledge | know | knowledgeable | knowledgeably |
| thought | think | thoughtful | thoughtfully |
| belief | believe | believable | believably |
| analysis | analyse | analytical | analytically |
| criticism | criticise | critical | critically |
| emphasis | emphasise | emphatic | emphatically |
| theory | theorise | theoretical | theoretically |
| practice | practise | practical | practically |
| logic | — | logical | logically |
| justification | justify | justifiable | justifiably |
| wisdom | — | wise | wisely |
| Noun | Verb | Adjective | Adverb |
|---|---|---|---|
| protection | protect | protective | protectively |
| reaction | react | reactive | reactively |
| production | produce | productive | productively |
| destruction | destroy | destructive | destructively |
| attraction | attract | attractive | attractively |
| competition | compete | competitive | competitively |
| repetition | repeat | repetitive | repetitively |
| addition | add | additional | additionally |
| collection | collect | collective | collectively |
| selection | select | selective | selectively |
| direction | direct | direct | directly |
| inspiration | inspire | inspiring | inspiringly |
| expectation | expect | expectant | expectantly |
| admiration | admire | admirable | admirably |
| operation | operate | operational | operationally |
| division | divide | divisive | divisively |
| provision | provide | provisional | provisionally |
| extension | extend | extensive | extensively |
| invitation | invite | inviting | invitingly |
| satisfaction | satisfy | satisfactory | satisfactorily |
| reliance | rely | reliable | reliably |
| persistence | persist | persistent | persistently |
| resistance | resist | resistant | — |
| tolerance | tolerate | tolerant | tolerantly |
| influence | influence | influential | influentially |
| variety | vary | various | variously |
| difference | differ | different | differently |
| appearance | appear | apparent | apparently |
| existence | exist | existing | — |
| effect | effect | effective | effectively |
| reason | reason | reasonable | reasonably |
| proof | prove | provable | provably |
| help | help | helpful | helpfully |
| use | use | useful | usefully |
| care | care | careful | carefully |
| Noun | Verb | Adjective | Adverb |
|---|---|---|---|
| happiness | — | happy | happily |
| sadness | sadden | sad | sadly |
| anger | anger | angry | angrily |
| fear | fear | fearful | fearfully |
| joy | rejoice | joyful | joyfully |
| pride | pride | proud | proudly |
| envy | envy | envious | enviously |
| courage | encourage | courageous | courageously |
| kindness | — | kind | kindly |
| honesty | — | honest | honestly |
| generosity | — | generous | generously |
| patience | — | patient | patiently |
| bravery | — | brave | bravely |
| laziness | — | lazy | lazily |
| curiosity | — | curious | curiously |
| jealousy | — | jealous | jealously |
| loyalty | — | loyal | loyally |
| politeness | — | polite | politely |
| shyness | — | shy | shyly |
| nervousness | — | nervous | nervously |
| hope | hope | hopeful | hopefully |
| doubt | doubt | doubtful | doubtfully |
| thanks | thank | thankful | thankfully |
| respect | respect | respectful | respectfully |
| wonder | wonder | wonderful | wonderfully |
| sympathy | sympathise | sympathetic | sympathetically |
| emotion | — | emotional | emotionally |
| faith | — | faithful | faithfully |
| grace | — | graceful | gracefully |
| harmony | harmonise | harmonious | harmoniously |
| intelligence | — | intelligent | intelligently |
| confidence | confide | confident | confidently |
| ignorance | ignore | ignorant | ignorantly |
| Noun | Verb | Adjective | Adverb |
|---|---|---|---|
| beauty | beautify | beautiful | beautifully |
| danger | endanger | dangerous | dangerously |
| fame | — | famous | famously |
| luck | — | lucky | luckily |
| fortune | — | fortunate | fortunately |
| comfort | comfort | comfortable | comfortably |
| success | succeed | successful | successfully |
| strength | strengthen | strong | strongly |
| width | widen | wide | widely |
| depth | deepen | deep | deeply |
| height | heighten | high | highly |
| weakness | weaken | weak | weakly |
| darkness | darken | dark | darkly |
| brightness | brighten | bright | brightly |
| sharpness | sharpen | sharp | sharply |
| freedom | free | free | freely |
| truth | — | true | truly |
| health | heal | healthy | healthily |
| wealth | enrich | wealthy | — |
| poverty | impoverish | poor | poorly |
| peace | pacify | peaceful | peacefully |
| power | empower | powerful | powerfully |
| harm | harm | harmful | harmfully |
| silence | silence | silent | silently |
| violence | — | violent | violently |
| elegance | — | elegant | elegantly |
| distance | — | distant | distantly |
| evidence | evidence | evident | evidently |
| importance | — | important | importantly |
| independence | — | independent | independently |
| accuracy | — | accurate | accurately |
| privacy | — | private | privately |
| simplicity | simplify | simple | simply |
| clarity | clarify | clear | clearly |
| purity | purify | pure | purely |
| intensity | intensify | intense | intensely |
| reality | realise | real | really |
| ability | enable | able | ably |
| stability | stabilise | stable | stably |
| popularity | popularise | popular | popularly |
| activity | activate | active | actively |
| possibility | — | possible | possibly |
| responsibility | — | responsible | responsibly |
| legality | legalise | legal | legally |
| mystery | — | mysterious | mysteriously |
| victory | — | victorious | victoriously |
| Noun | Verb | Adjective | Adverb |
|---|---|---|---|
| government | govern | governmental | — |
| politics | politicise | political | politically |
| economy | economise | economic | economically |
| industry | industrialise | industrial | industrially |
| agriculture | — | agricultural | agriculturally |
| science | — | scientific | scientifically |
| technology | — | technological | technologically |
| history | — | historical | historically |
| geography | — | geographical | geographically |
| culture | cultivate | cultural | culturally |
| nature | — | natural | naturally |
| environment | — | environmental | environmentally |
| society | — | social | socially |
| energy | energise | energetic | energetically |
| medicine | medicate | medical | medically |
| music | — | musical | musically |
| art | — | artistic | artistically |
| symbol | symbolise | symbolic | symbolically |
| identity | identify | identical | identically |
| democracy | democratise | democratic | democratically |
| tradition | — | traditional | traditionally |
| nation | nationalise | national | nationally |
| profession | — | professional | professionally |
| person | personalise | personal | personally |
| origin | originate | original | originally |
| season | season | seasonal | seasonally |
| accident | — | accidental | accidentally |
| occasion | — | occasional | occasionally |
| employment | employ | employed | — |
| growth | grow | growing | — |
| pollution | pollute | polluted | — |
| organisation | organise | organised | — |
| loss | lose | lost | — |
Endings such as -er, -or, -ist, -ian, -ant and -ee make nouns for people.
| Base word | Person noun |
|---|---|
| teach | teacher |
| act | actor |
| create | creator |
| inspect | inspector |
| employ | employer / employee |
| art | artist |
| science | scientist |
| music | musician |
| electric | electrician |
| politics | politician |
| assist | assistant |
| participate | participant |
| inhabit | inhabitant |
| study | student |
| lead | leader |
| write | writer |
| operate | operator |
| visit | visitor |
| collect | collector |
| invent | inventor |
In some families, the form with -ly has a different meaning from the form without it.
| Adjective | Adverb without -ly | Adverb with -ly |
|---|---|---|
| hard | hard (with effort) | hardly (almost not) |
| late | late (not on time) | lately (recently) |
| near | near (close) | nearly (almost) |
| high | high (far up) | highly (very) |
| short | short (suddenly) | shortly (soon) |
| direct | direct (straight) | directly (immediately) |
| most | most (to the greatest degree) | mostly (mainly) |
| fast | fast (quickly) | — (no -ly form) |
| good | well | — (the adverb of good is well) |
| free | free (without payment) | freely (without limit) |
Several adjectives come from the same base but mean different things. Learn each separately.
| Words | Difference |
|---|---|
| economic / economical | Economic relates to the economy; economical means saving money. |
| historic / historical | Historic means important in history; historical relates to history. |
| respectful / respectable / respective | Respectful shows respect; respectable deserves respect; respective means belonging to each one separately. |
| sensible / sensitive | Sensible shows good sense; sensitive is easily affected. |
| imaginary / imaginative | Imaginary means not real; imaginative means full of ideas. |
| successful / successive | Successful means achieving the aim; successive means one after another. |
| considerable / considerate | Considerable means large; considerate means thoughtful of others. |
| comprehensive / comprehensible | Comprehensive means complete; comprehensible means able to be understood. |
| electric / electrical | Electric is used with specific things (an electric guitar); electrical is used in general (electrical engineering). |
| bored / boring, interested / interesting | -ed describes how a person feels; -ing describes what causes the feeling. |
Change the word in brackets to fit the gap. The answers are in the right-hand column.
| Sentence | Answer |
|---|---|
| She made a quick ___ to accept the job. (decide) | decision |
| The team played ___ and won. (success) | successfully |
| He gave a very ___ speech. (inspire) | inspiring |
| The ___ of the environment is important. (protect) | protection |
| She spoke ___ about her plan. (confident) | confidently |
| This book is very ___. (inform) | informative |
| The ___ of the forest was shocking. (destroy) | destruction |
| He waited ___ for the results. (patience) | patiently |
| The ___ between the two schools was fierce. (compete) | competition |
| It is ___ to leave without saying goodbye. (polite) | impolite |
| She is very ___ about her work. (enthusiasm) | enthusiastic |
| The government wants to ___ the economy. (strong) | strengthen |
| The ___ was unexpected. (announce) | announcement |
| They are ___ of their success. (pride) | proud |
| He is a very ___ student. (diligence) | diligent |
Changing a verb or adjective into a noun is a common feature of formal writing. It makes sentences shorter and more academic.
| Simple sentence | More formal version |
|---|---|
| We decided quickly. | Our quick decision saved time. |
| Many people are polluting rivers. | The pollution of rivers is increasing. |
| Teachers educate students carefully. | The careful education of students matters. |
| The government acted fast. | The government's fast action surprised everyone. |
| It is important to protect forests. | The protection of forests is important. |
| Prices rose sharply. | There was a sharp rise in prices. |
| Students who revise regularly succeed. | Regular revision leads to success. |
| Mistake | Correct | Why |
|---|---|---|
| She is a success woman. | She is a successful woman. | An adjective is needed before the noun. |
| He sings beautiful. | He sings beautifully. | An adverb describes the verb. |
| I am very interest in history. | I am very interested in history. | Use the adjective after am. |
| The film was bored. | The film was boring. | -ing describes the cause; -ed describes the feeling. |
| The decide was hard. | The decision was hard. | A noun is needed after the. |
| She spoke confident. | She spoke confidently. | An adverb describes the verb. |
| Pollution is danger. | Pollution is dangerous. | An adjective is needed after is. |
| He is a really difference person. | He is a really different person. | Use the adjective different. |
| It is importance to study. | It is important to study. | An adjective is needed after is. |
| She hardly worked all night. | She worked hard all night. | Hardly means almost not. |
Activity: give each student ten base words and a blank table with four columns (noun, verb, adjective, adverb), and ask them to fill in the forms using a dictionary. Next, ask them to write one sentence for each form. For older students, give a short paragraph with gaps and bracketed words and ask them to complete it, as in an examination word formation task.
Please note: this guide uses British spelling. Some families have rare or informal forms that are not shown, and a dash means that no common form exists. Students should check a dictionary for any form they are unsure of.
10 questions. Select an answer for each, then submit to see your score instantly.