How to Create Negative Adjectives Using the Correct Prefix

This lesson will help you become familiar with the negative form of some common adjectives like "sufficient", "effective", and "appropriate" by showing the correct prefix to use with each.

Step #1: Test Yourself

For each adjective given below, choose the correct prefix in bold to add to the beginning in order to make it negative (ex. possible = impossible). The number of adjectives that work with each prefix is given in brackets. For example, there are 14 adjectives in the whole list that can use "un" as a prefix.

Un- (14) / Ir- (5) / In- (11) / Im- (5) / Il- (3)

able / sufficient / professional / replaceable / reliable / responsible / accurate / accessible / clear / proper direct / efficient / certain / complete / common / precise / decisive / important / satisfactory / relevant / patient / regular / practical / effective / capable / known / achievable / legal / significant / cooperative / stable / willing / adequate / logical / partial / appropriate / employed / rational / probable / likely / legitimate

Step #2: Check the Answers

Un-

unable, unprofessional, unreliable, unclear, uncertain, uncommon, unimportant, unsatisfactory, unknown, unachievable, uncooperative, unstable, unwilling, unemployed, unlikely

Ir-

irreplaceable, irresponsible, irrelevant, irregular, irrational

In-

insufficient, inaccurate, inaccessible, indirect, inefficient, incomplete, indecisive, ineffective, incapable, insignificant, inadequate, inappropriate

Im-

improper, imprecise, impatient, impractical, impartial, improbable

Il-

illegal, illogical, illegitimate

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Practice

Task #1: Find the one incorrect negative adjective in each set of adjectives below:

1. inadequate / inappropriate / ineffective / inregular / inaccurate

2. irrational / irresponsible / irachievable / irrelevant / irreplaceable

3. unefficient / unable / unlikely / unachievable / uncertain

4. improper / impolite / imcapable / impractical / improbable

5. illegal / ilwilling / illegitimate / illogical

Task #2: Fill in the blank with the correct negative adjective.

in + efficient / accurate / sufficient / adequate / appropriate / capable

1. We don’t have enough money in the budget to invest for growth. We have _____________ capital.

2. The statistics are presenting false information. They are completely _____________.

3. He’s like a child. He only wants things his way or nothing. He is ____________ of compromising.

4. The staff make a lot of mistakes because they don’t get enough training. The training is _____________.

5. He offended our business partners with his rude comments. This behavior was very _____________.

6. Our processes take much longer than they should and produce too much waste. Our operations are very _____________

ir + rational / replaceable / responsible / regular / relevant

1. She got fired because she was not taking her job seriously. She was acting very _____________.

2. Last week, three people on our team quit. People quit from time to time but three people in the same week is highly __________.

3. Tim, the founder of the company, retired last week. He knew our industry like the back of his hand. I’m sure that the new CEO will be good, but Tim is ______________.

4. He wastes a lot of time at our meetings and gets distracted. He always talks about _____________ topics.

5. Consumers like expensive things because they associate high prices with high value. It may seem __________ to want to pay more, but if they feel that they are getting value for their money, it actually makes sense.

un + able / certain / willing / likely / achievable

1. The labor union refuses to negotiate. They are _________ to return to work unless their contract changes.

2. We don’t know if the company will return to the workplace or continue to work from home. The whole situation remains very ____________.

3. Please notify us in advance if you are _________ to attend the meeting.

4. People need to believe that they are able to reach their goals. If their targets are ___________, they will not even try.

5. We don’t expect to get the contract. It’s very ___________.

im + patient / partial / proper / probable / practical

1. He was fired for __________ behavior at work, including watching live sports on his computer during worktime.

2. Spending all that money on company merchandise was ___________. Nobody was going to use it, so it was a waste of money.

3. I hate waiting for things. I’m quite an ____________ person.

4. It’s _________ that we’ll reach our targets this year. Business has been very slow.

5. It’s important that the people who are responsible for hiring new staff are ____________. They need to be fair and unbiased when deciding who to hire.

Answers

Task #1 - incorrect words are below with correct word in brackets:

1. inregular ("irregular" is correct)

2. irachievable ("unachievable" is correct)

3. unefficient ("inefficient" is correct)

4. imcapable ("incapable" is correct)

5. ilwilling ("unwilling" is correct)

Task #2:

in + efficient / accurate / sufficient / adequate / appropriate / capable

1. We don’t have enough money in the budget to invest for growth. We have insufficient capital.

2. The statistics are presenting false information. They are completely inaccurate.

3. He’s like a child. He only wants things his way or nothing. He is incapable of compromising.

4. The staff make a lot of mistakes because they don’t get enough training. The training is inadequate.

5. He offended our business partners with his rude comments. This behavior was very inappropriate.

6. Our processes take much longer than they should and produce too much waste. Our operations are very inefficient.

ir + rational / replaceable / responsible / regular / relevant

1. She got fired because she was not taking her job seriously. She was acting very irresponsible.

2. Last week, three people on our team quit. People quit from time to time but three people in the same week is highly irregular.

3. Tim, the founder of the company, retired last week. He knew our industry like the back of his hand. I’m sure that the new CEO will be good, but Tim is irreplaceable.

4. He wastes a lot of time at our meetings and gets distracted. He always talks about irrelevant topics.

5. Consumers like expensive things because they associate high prices with high value. It may seem irrational to want to pay more, but if they feel that they are getting value for their money, it actually makes sense.

un + able / certain / willing / likely / achievable

1. The labor union refuses to negotiate. They are unwilling to return to work unless their contract changes.

2. We don’t know if the company will return to the workplace or continue to work from home. The whole situation remains very uncertain.

3. Please notify us in advance if you are unable to attend the meeting.

4. People need to believe that they are able to reach their goals. If their targets are unachievable, they will not even try.

5. We don’t expect to get the contract. It’s very unlikely.

im + patient / partial / proper / probable / practical

1. He was fired for improper behavior at work, including watching live sports on his computer during worktime.

2. Spending all that money on company merchandise was impractical. Nobody was going to use it, so it was a waste of money.

3. I hate waiting for things. I’m quite an impatient person.

4. It’s improbable that we’ll reach our targets this year. Business has been very slow.

5. It’s important that the people who are responsible for hiring new staff are impartial. They need to be fair and unbiased when deciding who to hire.