Common prefixes with adjectives

Today's English lesson is about common prefixes with adjectives. 

What is a prefix?

A prefix is a letter or a group of letters that we put in front of a word to make a new word. 

Common prefixes with adjectives

We often use prefixes with adjectives to give them a negative meaning. We use different prefixes depending on the adjectives. Here are some examples: 

1) un- (= not)

happy => unhappy (i.e. not happy)

Thinking about money makes John happy. However, thinking about his job makes him unhappy.

reliable => unreliable (i.e. not reliable) 

My old car is unreliable, but my friend's new car is reliable. 

comfortable => uncomfortable (i.e. not comfortable)

This sofa is so comfortable. That hard chair is so uncomfortable. 

common => uncommon (i.e. not common)

It is uncommon for people to hate earning money, but it is common for people to hate their jobs. 

2) in- (= not)

convenient => inconvenient (i.e. not convenient)

Going to work by car is convenient. 
Going to work by public transport is inconvenient. 

capable => incapable (i.e. not capable)

Very young children are incapable of making decisions by themselves. 
Most adults are capable of making decisions by themselves. 

expensive => inexpensive (i.e. not expensive)

Plastic toys are inexpensive.
Hi-tech toys are very expensive. 

visible => invisible 

Everything we can see around us is visible. 
Everything we cannot see is invisible. 

3) im- (= not) We often use this prefix for adjectives beginning with the letters m or p.

polite => impolite (i.e. not polite)

It is polite to smile and say 'please' and 'thank you'.
It is impolite to sneeze at the table. 

patient => impatient (i.e. not patient)

Patient people often make good teachers. 
Impatient people should not become teachers. 

mature => immature (i.e. not mature)

Adults should behave in a mature way. 
I can't stand people who are immature. 

moral => immoral (i.e. not moral)

The couple's immoral deeds will be punished one day. 
What do you think it means to live a moral lifestyle?

4) il- (= not) We often use this prefix for adjectives beginning with the letter l.

legible (i.e. you can read it easily) => illegible (i.e. you cannot read it easily)

Some of John's classmates' handwriting is legible. 
Doctors' handwriting is usually illegible.

literate (i.e. you can read and write)  => illiterate (i.e. you cannot read and write)

Are most people in the world literate?
Some poor people in Africa are illiterate.

legal => illegal

It is illegal to kill another person.
It is legal for most adults to get married. 

5) ir- (= not) We often use this prefix for adjectives beginning with the letter 'r'.

regular (i.e. following a normal pattern) => irregular (i.e. not following a normal pattern)

'Play' is a regular verb in English. 
'Come' is an irregular verb in English.

relevant => irrelevant (i.e. not relevant)

If you have a relevant question, you may ask it at the end of the presentation.
Irrelevant questions will not be answered.

responsible => irresponsible (i.e. not responsible)

The company is looking for responsible employees to promote to management positions. 
Irresponsible employees will be monitored and may be be fired. 

rational => irrational (i.e. not rational)

Love is often irrational.
I think it is rational to believe that komodo dragons are dangerous.

6) dis- (= not)

honest => dishonest (i.e. not honest)

Honest people never tell lies or cheat. 
Dishonest people often tell lies or cheat.

obedient => disobedient (i.e. not obedient)

The obedient boy listened when the teacher told him to be quiet. 
The disobedient boy didn't listen when the teacher told him to be quiet. 

Please note: If you are not sure which prefix to use a good dictionary will be able to help you.

Lesson Vocabulary

sneeze (verb) => The woman is sneezing. 

komodo dragons (noun)

sofa (noun)

public transport (compound noun)


Your turn! Try to find one or two words for each of the prefixes below. Don't use the words from the lesson. :-) Try to find your own ones. 

(1) un- (2) in- (3) im- (4) il- (5) ir- (6) dis-

Please leave your answers in the comments section and I will gladly give you some feedback. Enjoy!


Elcio Miranda said...

(1) unfortunatelly, untrue, unforgetable
(2) insatisfied, inexperient, inoportune
(3) imaculate, (couldn´t find any other, give me some)
(4) il (can´t find)
(5) irreplaceble, irracional,
(6) diselegant,

Francois Oosthuizen said...

Thanks for doing the exercise, Elcio!

Here are my suggestions

Unfortunatelly = Unfortunately
- The spelling is incorrect.
- Please note that this is an adverb.

Unforgetable = Unforgettable
- The spelling is incorrect.

insatisfied = unsatisfied
- We use the prefix 'un-' with this adjective.

inexperient = inexperienced
- The spelling of this word is incorrect.

inoportune = inopportune
- The spelling of this word is incorrect.

- 'Im' is not a prefix in this word. It forms part of the root word.
- The spelling is incorrect.

irreplaceble = irreplaceable
- The spelling is incorrect.

irracional = irrational
- The spelling is incorrect.

diselegant = inelegant
- We use the prefix 'in-' with this adjective.

Anonymous said...

1. unforgetable, unemployment
2. invincible, indecent
3. immortal, improper
4. illumination
5. irreversible, irresistable


Francois Oosthuizen said...

1) unforgetable => unforgettable
2) 'In-' is not a prefix in the word 'invincible'. It forms part of the root of the word.
3) Correct!
4) 'Il-' is not a prefix in the word 'illumination'. It forms part of the root of the word.
5) 'Irresistible' is the correct spelling of the word. 'Ir-' is not a prefix in the word 'irresistible'. It forms part of the root of the word.

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