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Prefixes are groups of letters that are added to the start of words to change their meaning.

See some examples of how prefixes can change the meaning of words.

Most prefixes mean a similar thing when they're added to different words.

un- and in- usually mean ‘not’. For example:

• unhappy
• unlocked
• intolerant
• incapable

dis- and mis- usually have negative meanings. For example:

• disagree
• disobey
• misbehave
• mislead

re- usually means ‘again’ or ‘back’. For example:

• redo
• reappear
• redecorate

sub- usually means ‘under’. For example:

• subheading
• submarine

There are spelling rules to follow when you add prefixes to words.

Watch this clip to learn to learn more about these rules and see some examples.

Remember

Root words are the basic words that are used to form other words. Root words haven't had any prefixes or suffixes added to them yet.

Not all prefixes can be added to all root words. You have to choose the correct one.

For example, un- can be added to 'happy' to make 'unhappy', but dis- or mis- cannot.

Adding in- can be particularly tricky. There are three rules to remember.

1. When the root word begins with an 'l', the prefix in- changes to il-. For example:

il + legal = illegal

2. When the root word begins with an 'r,' the prefix in- changes to ir-. For example:

ir + regular = irregular

3. When the root word begins with an 'm' or a 'p', the prefix in- changes to im-. For example:

im + possible = impossible

Complete the prefixes quiz. Can you get all five answers correct?

Read each word that comes up and decide which prefix could be added to it.

Read the groups of root words in the table below.

Decide which group the prefixes un-, mis- and dis- go with.

Top Tip - Read all the words in the list and then read all of them with each prefix before you decide.

Below are six prefixes and six root words.

Match up each prefix with the correct root word and write a sentence which includes that new word.

Prefixes

• ir-

• dis-

• re-

• sub-

• mis-

• un-

Root words

• responsible

• read

• build

• like

• lucky

• way

You can check your answers using this

Add the correct spelling of the in- prefix to the following words.

• ___active
• ___clude
• ___legal
• ___logical
• ___regular
• ___rational
• ___possible
• ___mature
• ___moral

Now choose three words from the list and use each of them in a full sentence. For example:

I was very inactive because I had hurt my ankle.