Prefixes

A prefix is a group of letters added to the beginning of a word to change its meaning. When you add a prefix, you create a new word with a different meaning.

What You'll Learn

In this lesson, you will learn:

• What prefixes are and how they change the meaning of a word
• Five common prefixes: un-, re-, pre-, mis-, and dis-
• How to work out the meaning of a new word by looking at its prefix

When to Use

1. To show the opposite (un-, dis-): "She was unhappy about the cancelled trip." (un- = not)
2. To mean "do again" (re-): "Please rewrite the sentence neatly." (re- = again)
3. To mean "before" (pre-): "We had a preview of the film before it opened." (pre- = before)
4. To mean "wrongly" (mis-): "I misread the question and got it wrong." (mis- = wrongly)

How to Form

Adding a Prefix

A prefix is placed directly in front of the base word. You do not change the spelling of the base word.

Prefix Meanings at a Glance

Key Rules

1. Do not change the base word: When you add a prefix, keep the spelling of the base word exactly the same. un + happy = unhappy (not "unhappy" with missing letters).

2. Double letters can happen: If the prefix ends with the same letter the base word starts with, you keep both letters. mis + spell = misspell (two s's). dis + satisfy = dissatisfy (two s's). un + necessary = unnecessary (two n's).

3. un- and dis- both mean "not" but are not interchangeable: Some words take un- (unhappy, unfair) and others take dis- (disagree, dislike). You need to learn which prefix goes with which word.

4. re- means "again": Adding re- shows the action is done a second time. "Read" means to read; "reread" means to read again.

5. Prefixes change meaning, not word class: The new word stays the same type as the base word. If the base word is an adjective (happy), the prefixed word is still an adjective (unhappy). If the base word is a verb (write), the prefixed word is still a verb (rewrite).

Common Mistakes

Clue Words

Prefixes that mean "not" or "opposite"

un-, dis-

Prefix that means "again"

re-

Prefix that means "before"

pre-

Prefix that means "wrongly"

mis-

Common prefixed words you will see often

unhappy, unkind, unfair, untidy, redo, rewrite, replay, preview, preheat, misspell, misread, dislike, disagree, disappear

Tip: When you see a long word you do not know, check if it starts with un-, re-, pre-, mis-, or dis-. Cover the prefix with your finger and read the base word first. Then add the prefix meaning to work out the full meaning!

Practice Tips

1. Cover and reveal: Cover the prefix with your finger. Read the base word first, then uncover the prefix and combine the meanings. For "rebuild": "build" means to make something; "re-" means again; so "rebuild" means to build again.

2. Prefix sorting game: Write ten words on cards. Sort them into five groups by prefix (un-, re-, pre-, mis-, dis-). This helps you remember which prefix goes with which words.

3. Opposite pairs: Practise matching words with their prefixed opposites: happy/unhappy, fair/unfair, like/dislike, agree/disagree, honest/dishonest.

4. Double-letter check: After writing a prefixed word, count the letters where the prefix meets the base word. If the prefix ends and the base word starts with the same letter, make sure you have written both.

Quick Reference