What is a suffix?
A suffix is a group of letters added to the end of a word. Suffixes change the word’s meaning, and often its part of speech.
- help → helpful (adjective)
- kind → kindness (noun)
- quick → quickly (adverb)
- teach → teacher (noun: a person who teaches)
Two kinds of suffixes
Inflectional suffixes
An inflectional suffix changes tense, number or comparison, but the word stays the same part of speech.
| Suffix | Job | Example |
|---|---|---|
| -s, -es | plural or present tense | cats, watches |
| -ed | past tense | jumped |
| -ing | ongoing action | jumping |
| -er | comparative | taller |
| -est | superlative | tallest |
Derivational suffixes
A derivational suffix creates a new word, often a different part of speech.
| Suffix | Meaning | Makes a… | Examples |
|---|---|---|---|
| -er, -or | person who | noun | baker, actor |
| -ness | state of being | noun | sadness, darkness |
| -ment | action or result | noun | movement, payment |
| -tion, -sion | act or process | noun | action, decision |
| -ful | full of | adjective | joyful, careful |
| -less | without | adjective | fearless, hopeless |
| -able, -ible | can be | adjective | readable, visible |
| -ous | full of | adjective | famous, dangerous |
| -y | having | adjective | rainy, sandy |
| -ly | in a way | adverb | slowly, happily |
| -ify, -ize | to make | verb | simplify, organize |
Three spelling rules
Adding a suffix sometimes changes the spelling of the base word. Three rules cover most cases.
1. Drop the e rule
If a word ends in silent e and the suffix starts with a vowel, drop the e. This is the drop the e rule.
- hope + ing → hoping
- care + ed → cared
- love + able → lovable
Keep the e if the suffix starts with a consonant: hopeful, careless, lovely.
2. The doubling rule
If a one-syllable word ends in one vowel + one consonant, double the consonant before a suffix that starts with a vowel. This is the doubling rule.
- hop + ing → hopping
- big + est → biggest
- run + er → runner
Do not double if there are two vowels or two consonants: rain → raining, jump → jumping. Never double w, x or y: snowing, boxer, playing.
3. Change y to i rule
If a word ends in consonant + y, change y to i before most suffixes. This is the change y to i rule.
- happy + ness → happiness
- carry + ed → carried
- funny + est → funniest
Keep the y before -ing: carrying, crying. Keep the y after a vowel: played, enjoyment.
Using suffixes to read and understand
Suffixes give clues about a word’s job. A word ending in -ly is usually an adverb. A word ending in -tion is usually a noun. A word ending in -ful is usually an adjective. When you meet a long new word, break it apart: care | ful | ly → "in a way that is full of care".
Worked examples
Example 1: Add -ing to swim. → swimming (one vowel + one consonant: double).
Example 2: Add -ness to lazy. → laziness (consonant + y: change to i).
Example 3: Add -ful to grace. → graceful (consonant suffix: keep e).
Example 4: What part of speech is enjoyment? → Noun (-ment).
Common mistakes
- runing ✗ → running ✓
- happyness ✗ → happiness ✓
- makeing ✗ → making ✓
- carefull ✗ → careful ✓ (-ful has only one l)
Try it yourself
- Add -ed: stop, try, bake, play.
- Add -est: hot, happy, nice.
- Make a noun: kind, move, decide.
- What does fearless mean?
Answers: 1. stopped, tried, baked, played. 2. hottest, happiest, nicest. 3. kindness, movement, decision. 4. Without fear.
Tip for families
Pick a base word, like play, and see how many words your family can build with suffixes in two minutes: plays, played, playing, player, playful, playfully, playfulness. Talk about how the meaning changes each time.
Quick recap
- A suffix goes at the end of a word.
- Inflectional suffixes change tense or number; derivational suffixes make new words.
- Learn the drop the e, doubling and change y to i rules.
- Suffixes give clues about a word’s part of speech.