Prefixes and suffixes
What is the difference between "helpful" and "helpless"? Between "import" and "export"? It is all about prefixes and suffixes!
Prefixes and suffixes are word parts that change meaning and function. Learning them helps you understand and spell many new words — even ones you have never seen before.
What are prefixes and suffixes?
A prefix is added to the beginning of a word:
happy → unhappy
A suffix is added to the end:
help → helpful
They can change meaning, word class, or both.
Common prefixes (meaning changes)
un- (not): unhappy, unfair
re- (again): redo, rewrite
pre- (before): preview, prepare
mis- (wrongly): mistake, misuse
dis- (opposite): disagree, disappear
over- (too much): overeat, overwork
sub- (under): submarine, subway
IN- and its variations
The prefix in- means "not", but it changes form depending on the next letter:
im- before b, m, p → impossible, impatient
il- before l → illegal
ir- before r → irregular
This makes pronunciation easier — it is not random.
Suffixes that form nouns
-ness: happiness, darkness
-ment: movement, agreement
-tion / -sion: information, decision
These often turn adjectives or verbs into nouns.
Suffixes that form adjectives
-ful (full of): helpful, careful
-less (without): helpless, careless
-able / -ible: readable, possible
These describe qualities or abilities.
Changing word class
Suffixes often change the type of word:
hope (noun) → hopeful (adjective)
quick (adjective) → quickly (adverb)
This helps you build more precise sentences.
Spelling changes when adding suffixes
Adding suffixes can change spelling:
Drop final E:
make → making
Change Y to I:
happy → happier → happiness
Double consonant (short vowel):
run → running
These rules help keep pronunciation consistent.
How prefixes and suffixes help you understand words
You can often guess meaning by breaking a word into parts:
un + helpful = not helpful
re + write = write again
This is especially useful for longer or unfamiliar words.
Key idea
Prefixes and suffixes are building blocks of English vocabulary.
Learning them helps you read, spell, and understand new words more efficiently.
