English
What is a prefix?
Quick answer
A prefix is a group of letters added to the start of a word to change its meaning, like un- in unhappy, re- in replay or dis- in disappear.
In one sentence
A prefix is a group of letters added to the start of a word to change its meaning, like un- in unhappy, re- in replay or dis- in disappear.
Explained
Take the word happy. Add un- to the front and you get unhappy, which means "not happy". Un- is the prefix, and happy is the root word (also called the base word).
Prefixes are useful because one prefix explains dozens of words. Once you know that re- means "again", you can work out redo, rebuild, reread, refill and replay.
Common prefixes
| Prefix | Meaning | Examples |
|---|---|---|
| un- | not / reverse | unkind, untie, unpack |
| dis- | not / opposite | disagree, dislike, disappear |
| mis- | wrongly | misspell, misbehave, mislead |
| re- | again / back | replay, return, rebuild |
| pre- | before | preview, prehistoric |
| in-, im-, il-, ir- | not | incorrect, impossible, illegal, irregular |
| sub- | under | submarine, subway |
| super- | above / beyond | superhero, superstar |
| inter- | between | international, interact |
| anti- | against | antifreeze, antiseptic |
| auto- | self | autograph, autobiography |
Working out a new word
Worked example: misunderstand.
- Spot the prefix: mis-, which means "wrongly".
- Find the root word: understand.
- Put the meanings together: to understand something wrongly.
Spelling tip: adding a prefix almost never changes the spelling of the root word. Just join them: dis + satisfied = dissatisfied, mis + spell = misspell, un + necessary = unnecessary. A double letter appears only when the prefix ends with the same letter the root starts with.
Many prefixes make antonyms: possible / impossible, tidy / untidy, honest / dishonest. Letters added to the end of a word are suffixes, as in care-ful and kind-ness. A prefix can also add a syllable at the front, so split long words at the prefix to read them: un-be-liev-a-ble.
submarine
bike
planet
Examples
- The magician made the rabbit disappear.
- Please rewrite this neatly.
- It is impolite to interrupt.
- She misread the sign and took the wrong bus.
- My uncle unpacked the groceries.
Common mistakes
- Dropping or adding letters. This is the most common mistake: dissapear (should be disappear), mispell (should be misspell).
- Picking the wrong "not" prefix: unpossible should be impossible. Learn the common pairs.
- Thinking every word starting with these letters has a prefix. Uncle and real are not un- + cle or re- + al.
Quick quiz
Prefixes
Check what you know with 5 quick questions.
Question 1 of 5
What does the prefix un- usually mean?
Practise it
Try it
- What does preview mean?
- Add a prefix to make the opposite of agree.
- How do you spell mis + step?
Answers: 1) To see something before (ahead of time). 2) Disagree. 3) Misstep, with a double s.
Spelling practice with prefixes
Practise it step by step in a full course: Grade 4 English
For grown-ups
Related topics
Suffixes
A suffix is a group of letters added to the end of a word to change its meaning or job, like -ful in helpful, -ness in kindness or -ed in jumped.
Antonyms
An antonym is a word that means the opposite of another word, like hot and cold, up and down, or happy and unhappy.
Syllables
A syllable is a beat in a word, built around one vowel sound. Cat has one syllable, rab-bit has two, el-e-phant has three.
Synonyms
A synonym is a word that means the same or nearly the same as another word, like big and large, or happy and cheerful.
Greek and Latin roots
Greek and Latin roots are word parts that carry a meaning, like bio (life), graph (write) and port (carry). Knowing them helps you work out words such as biography or transport.
Homophones
Homophones are words that sound the same but have different meanings and usually different spellings, like there, their and they're, or see and sea.