Skip to main content
Academy11+

11+ English · Topic explained

Prefixes

How can two letters turn "happy" into its opposite?

The big idea

A prefix is a group of letters added to the start of a word to change its meaning.

Picture it

A prefix is a building block clicked onto the front of a word.

Key words

prefix
Letters added to the start of a word.
root word
The word you start with, before adding anything.
not prefixes
un-, dis-, in-, im-, il-, ir- all mean not.
other prefixes
re- (again), pre- (before), mis- (wrongly), sub- (under), anti- (against).

Worked examples

  1. 1Warm-up

    un + happy = unhappy

    • un- means not.
    • unhappy means not happy.
  2. 211+ standard

    impossible illegal irregular

    • im- usually goes before p or m (impossible, immature).
    • il- before l, ir- before r.
  3. 311+ standard

    dis + appear = disappear un + necessary = unnecessary

    • Never change the root word's spelling.
    • unnecessary has two n's: one from un-, one from necessary.
  4. 411+ standard

    reappear preview submarine anticlockwise

    • re- again, pre- before, sub- under, anti- against.
    • Knowing the prefix helps you work out new words.

The common mistake

The mistake

"mispell", "dissappear"

Instead

misspell, disappear

Why: Just add the prefix; the root word's spelling never changes. mis + spell keeps both s's; dis + appear only has one.

Where it comes up in the 11+

Choosing the prefix that makes an opposite, and spelling prefixed words, come up in SPaG, cloze and verbal reasoning.

The video

Video coming soon

We're making a short video that explains prefixes step by step. Until then, everything it covers is on this page.

Free printable

Prefixes worksheet

Practice questions on this topic to print and try on paper, at home or on the way to school.

Download the worksheet (PDF)

Free account needed: it takes a minute.

Quick quiz

Have a go first, then tap to see the answer.

  1. 1. Which prefix makes the opposite of "patient"?

    • un
    • im
    • dis
    • ir
    Show the answer

    im

    impatient: im- often goes before p.

  2. 2. Which is spelt correctly?

    • dissappear
    • disappear
    • disapear
    Show the answer

    disappear

    dis + appear: one s from dis, two p's from appear.

  3. 3. What does "pre" mean in "preheat"?

    • after
    • again
    • before
    • not
    Show the answer

    before

    You preheat the oven before cooking.