Suffixes That Change a Word’s Job

Prefixes change what a word means. Suffixes often change what a word does. By adding a suffix, you can turn a verb into a noun, a noun into an adjective, or an adjective into an adverb. Understanding suffixes helps you recognise a word’s job, called its part of speech, even when you have never seen the word before.

Noun suffixes

These suffixes usually create nouns, words for people, things or ideas.

Example

Start with the verb invent. Add -or and you get inventor, the person who invents. Add -ion and you get invention, the thing invented. One base word, three words.

Adjective suffixes

These suffixes usually create adjectives, words that describe nouns.

Opposite suffixes

-ful and -less are opposites: fearful means full of fear, while fearless means without fear. The difference of one suffix can completely flip a description of a character.

Verb and adverb suffixes

• -ize or -ise and -ify often create verbs: modernize, simplify, classify.
• -en can create verbs too: strengthen, brighten.
• -ly usually creates adverbs from adjectives: quick becomes quickly, careful becomes carefully.

Spelling note

American English usually spells -ize (organize), while British English often uses -ise (organise). Both are correct; just be consistent in your writing.

Word families

A word family is a group of words built from the same base with different suffixes.

Using suffixes in reading

When you meet an unfamiliar word, its suffix tells you its likely job. In the sentence The scientist’s hypothesis was testable, you may not know testable yet, but -able tells you it is an adjective meaning “able to be tested”.

Using suffixes in writing

Suffixes help you vary your sentences. Instead of She showed a lot of creativity in a creative way, try She solved the problem creatively. Choosing the right form makes your writing smoother.

Example in a science text

Read this sentence: The researchers observed a measurable improvement in the plants’ growth after adding fertiliser. Two suffixes do a lot of work here. Measurable (-able) is an adjective telling us the improvement could be measured. Improvement (-ment) is a noun naming the result of improving. Even if a word in a science text is new to you, its suffix often tells you whether it names a thing, describes something or names an action, which is a big step toward understanding the whole sentence.

Stacking suffixes

Words can carry more than one suffix: care + -ful + -ly = carefully; hope + -less + -ness = hopelessness. Peel them off one at a time from the end.

Key takeaways

• Suffixes often change a word’s part of speech.
• -tion, -ment, -ness and -ity usually signal nouns; -er, -or and -ist signal people.
• -ful, -less, -able and -ous usually signal adjectives; -ly usually signals adverbs.
• A word family shares a base but uses different suffixes for different jobs.

Practice

Complete the word family for act: a person who acts (noun), the thing done (noun), describing someone who does a lot (adjective), and in a lively way (adverb).

Answers: actor, action, active, actively.