Prefix in English with Rules and Examples • Englishilm

English Prefixes Made Easy! A prefix is a group of letters added to the beginning of a word to change its meaning. Learning common prefixes helps you understand new words, build your vocabulary, and use English more confidently. In this lesson, you will learn common English prefixes with simple rules and easy examples. These examples will show how prefixes change the meaning of words. By learning these, you will improve your English reading, writing, and speaking skills step by step.

Table of Contents

What is a Prefix?

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

Example:

un + happy = unhappy (not happy)
re + play = replay (play again)

Why Are Prefixes Important?

Prefixes help you understand new words quickly.
They can change the meaning to negative, opposite, again, before, etc.
Prefixes improve vocabulary and speaking skills in English.

Common Prefixes and Their Meanings

Prefixes That Show Not or Opposite

Prefix	Meaning	Example	Use in Sentence
un-	not	unhappy	She is unhappy today.
in-	not	incorrect	That answer is incorrect.
im-	not	impolite	It is impolite to interrupt.
ir-	not	irregular	He has an irregular schedule.
il-	not	illegal	That act is illegal.
dis-	opposite of	disagree	I disagree with you.
non-	not	nonsense	That is complete nonsense.

Prefixes That Show Again or Back

Prefix	Meaning	Example	Use in Sentence
re-	again	replay	Let’s replay the song.
retro-	back, past	retroactive	It’s a retroactive payment.

Prefixes That Show Time or Order

Prefix	Meaning	Example	Use in Sentence
pre-	before	preview	I watched the preview.
post-	after	postwar	This happened in the postwar era.
fore-	before	forecast	The forecast says it will rain.

Prefixes That Show Direction, Degree, or Location

Prefix	Meaning	Example	Use in Sentence
sub-	under/below	submarine	A submarine goes underwater.
super-	above	superman	He’s like a superman!
inter-	between	international	It was an international event.
intra-	within	intranet	The company uses an intranet.
trans-	across/through	transport	We will transport goods.

Prefixes That Show Numbers or Quantity

Prefix	Meaning	Example	Use in Sentence
mono-	one	monolingual	He is monolingual.
bi-	two	bicycle	She rides a bicycle.
tri-	three	triangle	A triangle has three sides.
multi-	many	multicolor	She wore a multicolor dress.
semi-	half	semicircle	The road is shaped like a semicircle.

Structure for Prefix Formation

Structure:
Prefix + Root Word = New Word

Structure	Example	Meaning
un + happy	unhappy	not happy
re + write	rewrite	write again
pre + heat	preheat	heat before
dis + connect	disconnect	break the connection
in + correct	incorrect	not correct
sub + title	subtitle	title below

Rules for Using Prefixes

1. Do not add a hyphen between prefix and word (except in rare compound forms).

✅ unhappy ❌ un-happy

2. The spelling of the root word usually stays the same.

correct → incorrect

3. Some prefixes change slightly depending on the word:

Use im- before b, m, p (e.g., impossible, imbalance)
Use ir- before r (e.g., irregular)
Use il- before l (e.g., illegal)

4. Prefixes do not stand alone – they need a root word to make meaning.

Prefixes that Can Create Nouns or Adjectives

Prefixes mostly change the meaning of a word but don’t usually change its part of speech (noun, adjective, verb, etc.) as often as suffixes do.

But — there are some prefixes that can create new nouns or adjectives, or at least modify them to express time, direction, quality, or attitude.

Prefixes That Can Help Form New Nouns

Prefix	New Noun	Meaning	Example in Sentence
co-	co-worker	a person who works with you	My co-worker is very helpful.
ex-	ex-president	former person in role	The ex-president gave a speech.
self-	self-esteem	about oneself	She has high self-esteem.
anti-	antivirus	against something	I installed new antivirus software.
non-	nonsense	not making sense	That’s just nonsense!
sub-	subgroup	a smaller group	He’s part of a subgroup in the team.

Prefixes That Can Help Form or Modify Adjectives

Prefix	New Adjective	Meaning	Example in Sentence
un-	unhappy	not happy	He was unhappy with the result.
dis-	dishonest	not honest	That was a dishonest answer.
in-	incomplete	not complete	The work is still incomplete.
im-	impolite	not polite	It’s impolite to talk loudly.
ir-	irregular	not regular	His heartbeat is irregular.
over-	overconfident	too confident	She is overconfident sometimes.
under-	underpaid	not paid enough	Nurses are often underpaid.

Differences Between Suffixes and Prefixes

	Suffixes	Prefixes
Change part of speech?	✅ Yes—noun, adjective, verb	🔸 Rarely—usually change meaning only
Position in word	At the end	At the beginning
Examples	kind → kindness, care → careful	happy → unhappy, honest → dishonest
Mostly used to	Form new word types	Change meaning