A prefix is a letter or group of letters added to the beginning of a word. Knowing what a prefix means can help us to understand new words.
There are many different prefixes that change a word into its antonym (opposite).
lucky / unlucky
appear / disappear
visible / invisible
possible / impossible
legal / illegal
In this worksheet you can practise choosing the correct prefix to create antonyms. You may find a dictionary helpful if you are not sure which one is correct.