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Negative Prefixes

In this lesson students practice using negative prefixes. Go over the chart with your students and have them complete the practice exercises.

Prefix Meaning Examples and Notes
un   not; the opposite of unusual, unfriendly, unimportant
“un” is the most common negative prefix.
in not; the opposite of inefficient, inappropriate, ineffective
“in” is the second most common negative prefix.
Many words that begin with “in” do not contain prefixes (insist, initially, insult, for example). Also, the prefix “in” has two meanings. It can be used to mean “not; the opposite of” or “within” (inside, in-house, etc.).
im not; the opposite of impossible, imperfect, immeasurable, impartial
Words that take “im” as a negative prefix always begin with an “m” or a “p” (imbalance is the one exception). However, not all adjectives that start with an “m” or “p” take “im” as a negative prefix (unmistakable, unpopular, unimportant, for example).
il not; the opposite of illegal, illegitimate, illegible, illiterate, illogical
Words that take “il” as the negative prefix always begin with the letter “i”. However, not all words that begin with “i” take “il” as a negative prefix (unlicensed, for example).
ir not; the opposite of irregular, irrational, irresponsible
Words that take “ir” as a negative prefix always begin with the letter “r”.
non not nonsense, nondairy, nonfiction, nonprofit, nontoxic
a not atypical, apolitical, asymmetrical
de used to communicate the reversal of an action. deactivate, deconstruct, declassify, decompose, deform
dis 1. used to communicate the reversal of an action.
2. not; the opposite of
1. disconnect, disable
2. disagree, disapprove, dishonest
mis   wrongly misfire, misguide, mislead, misinform
anti against antisocial, anti-inflammatory 
dys bad or difficult dysfunctional, dyslexic 



Negative Prefix Practice 1: un, in, im, il, and ir

Cut out the words.  Have students separate the words into the following categories:

1. words that take “un” as a negative prefix
2. words that take “in” as a negative prefix
3. words that take “im” as a negative prefix
4. words that take “il” as a negative prefix
5. words that take “ir” as a negative prefix

able equal secure professional rational perfect believable
responsible literate accurate accessible sufficient regular clear
do complete fair common precise fortunate important
relevant polite aware pure efficient grateful justifiable
direct active valid veil mature consistent reversible
comfortable identified effective friendly capable known achievable
legal reliable logical conspicuous appropriate employed usual
expected reasonable flexible willing legitimate adequate certain
patient stable cover replaceable significant possible cooperative



Negative Prefix Practice 2: non, a, de, dis, mis, anti, and dys

Have students fill in the blanks with a word containing a negative prefix.

We flew from Tokyo to London without stopping in any other cities. Our flight was _________.
I’m sorry,  you can’t smoke here. This is a  _________ area.

Is this uncommon? Yes, it’s extremely _________.
I don’t understand why the Republicans and Democrats are blaming each other for this. To me, it’s definitely an _________ issue.

Is there any way to _________ the alarm on my car? It keeps going off in the middle of the night.
I’m drinking a lot of water because I don’t want to get __________.
Yelling at your employees is a good way to _________them.

One of the _________  of operating in the U.S. is the high labor costs.
Some of the runners were _________ for using performance-enhancing drugs.

It might not have been an outright lie, but what he said was definitely _________.
You should always use spell checker to make sure you haven’t _________ anything.
When speaking English to non-native speakers, you should avoid using obscure idioms to make sure they don’t _________ you.

The doctor prescribed me some _________ to get rid of the infection.
My roommate has been very _________ lately. He spends all his time in his room playing video games and never comes out to talk.

He comes from a _________ family, but he became successful anyway.
Are you optimistic about the future?  Do you think it will be a utopia or a _________ ?


non-stop, non-smoking, atypical, apolitical, deactivate, dehydrated, demotivate, disadvantages, disqualified, misleading, misspelled, misunderstand, antibiotics, antisocial, dysfunctional, dystopia