Skip to main content
Academy11+
Back to Spelling and vocabulary

English · Guide 3 of 4

Prefixes and suffixes

A prefix goes at the start of a word and changes its meaning (happy → unhappy). A suffix goes at the end and often changes the word's job (happy → happiness). Learn the common ones and you can unlock hundreds of words.

  • Ages 9 to 11
  • 11+ English
  • Worked examples

What is it?

The main part of a word is its root word. A prefix is a group of letters added to the front (un + kind = unkind). A suffix is added to the end (kind + ness = kindness).

11+ questions ask you to make the opposite of a word with the right prefix, add a suffix to change a word's class (enjoy → enjoyment), or work out what an unfamiliar word means from its parts.

A typical question, and the parts to learn

Which prefix makes the opposite of possible: un, dis, im or mis?

Common prefixes
PartMeaningExamples
un-notunhappy, unkind
dis-not, or the oppositedisagree, disappear
mis-wronglymisspell, misbehave
re-again, or backrebuild, return
pre-beforepreview, prehistoric
in- / im- / il- / ir-notinvisible, impossible, illegal, irregular
sub-undersubmarine, subway
super-above, more thansuperstar, supermarket
anti-againstantiseptic, anticlockwise
inter-betweeninternational, interact
auto-selfautograph, autobiography
bi- / tri-two / threebicycle, triangle
semi-halfsemicircle, semi-final
Common suffixes
PartMeaningExamples
-fuladjective: full ofhopeful, careful
-lessadjective: withouthopeless, careless
-nessnounkindness, darkness
-mentnounenjoyment, payment
-lyadverb (how)quickly, happily
-able / -ibleadjective: can bereadable, visible
-ise / -ifyverbapologise, simplify
-er / -estmore / mosttaller, tallest

How to spot it

  • 'Add a prefix to make the opposite of…' or 'Which prefix completes the word?'.
  • 'Add a suffix to make a noun / adjective / adverb'.
  • 'What does the prefix sub- mean?' or a long word you need to break into parts.
  • Spelling lines with words like 'misspell', 'unnecessary' or 'happily'.

Step-by-step method

  1. Step 1: Find the root word: cover any letters at the start and end that look like a prefix or suffix.
  2. Step 2: For an opposite, try each prefix in your head: unpossible? dispossible? impossible ✓. The right one sounds familiar.
  3. Step 3: Use the 'not' rule for in-: im- before m or p (immature, impatient), il- before l (illegal), ir- before r (irregular).
  4. Step 4: A prefix never changes the root's spelling: dis + satisfied = dissatisfied, mis + spell = misspell, un + necessary = unnecessary.
  5. Step 5: A suffix can: use your spelling rules (drop the e, change y to i, double the consonant). happy + ly = happily; hope + ing = hoping.
  6. Step 6: Check the word class you've made: -ness and -ment make nouns, -ful and -less make adjectives, -ly usually makes an adverb.

Worked examples

Example 1: the opposite with a prefix

Question: Write the opposite of 'legal', 'patient' and 'regular'.
  1. Step 1: All three take a 'not' prefix from the in- family.
  2. Step 2: legal starts with l → il: illegal. patient starts with p → im: impatient. regular starts with r → ir: irregular.
  3. Step 3: Notice the double letters: illegal, irregular. Nothing has been removed from the root word.

Answer: illegal, impatient, irregular

Example 2: a prefix with a double letter

Question: Add 'mis' to 'spell' and 'dis' to 'satisfied'.
  1. Step 1: Just join them: mis + spell = misspell. dis + satisfied = dissatisfied.
  2. Step 2: The double s is correct: one s from the prefix, one from the root.

Answer: misspell, dissatisfied

Example 3: changing the word class

Question: Turn 'enjoy' into a noun, 'care' into an adjective, and 'happy' into an adverb.
  1. Step 1: Noun: enjoy + ment = enjoyment.
  2. Step 2: Adjective: care + ful = careful (or careless). Keep the e: -ful starts with a consonant.
  3. Step 3: Adverb: happy + ly: change y to i → happily.

Answer: enjoyment, careful, happily

Example 4: working out a new word

Question: What does 'semicircle' mean? What about 'submerge'?
  1. Step 1: semi- means half, so a semicircle is half a circle.
  2. Step 2: sub- means under, and 'merge' is to join or mix in. To submerge is to go under the surface (of water).

Answer: half a circle; to go under water

Common traps

  • Dropping a letter from the root

    'misspell' has two s's and 'unnecessary' has two n's. Don't drop a letter where the prefix meets the root.

  • The wrong 'not' prefix

    It's 'unhappy', not 'inhappy', and 'disagree', not 'unagree'. If you're unsure, say each one aloud: the real word usually sounds familiar.

  • -ful with two l's

    The suffix is always -ful: hopeful, wonderful, thankful.

  • Forgetting y → i

    happy + ness = happiness, not happyness. beauty + ful = beautiful.

Top tips

  • Collect word families: port (carry) gives transport, portable, export, import.
  • Learn the in-/im-/il-/ir- rule by the first letter of the root: im + p/m, il + l, ir + r.
  • When you meet a long word, draw lines between prefix | root | suffix: un | believ | able.
  • If an answer option has a prefix meaning 'not', it probably means the opposite of the root.

Practice questions

Practise this with a free account

12 practice questions on this topic, from easy to 11+ level. Reading the guide is free for everyone; practice is for members, and signing up is free.

Sign up free to practiseSign in

Related on Academy11+

More free help with the same topic, on screen and on paper.