Image by Helga Weber on Flickr.com is licensed under CC BY 2.0.

I don’t ever want my readers to get negative about learning English, which is why I try to keep this blog upbeat and interesting, but today we are going to focus on something…negative. This post isn’t about being negative. Instead it is about using negative prefixes in English.

To start, there are many different prefixes in English that can be added to words to negate, or make them negative.

Here are some common ones:
dis-
il-
im-
in-
ir-
non-
un-

These prefixes can be added to many root words to make the root words negative.

For example:
If I have the root word, interested, and I add the prefix dis- to the front of the word, I now have, disinterested, which means not interested.

All of the prefixes above have the same basic meaning, they mean ‘not.’

Here are some more examples of negative words that are formed by adding a prefix:

disability – not having an ability; a lack of ability
illogical – not logical
imbalance – not in balance
inappropriate – not appropriate
irrational – not rational
noncompliant – not compliant
unfortunate –not fortunate or lucky

So, how do you know which negative prefix to use with which word when there are so many of them? I am sad to say there is no good rule for when to use one negative prefix over another with a certain root word.

Learning to use the appropriate negative prefix with the right root word is something you have to learn from listing, reading, and speaking English as much as you can. Most words in English can only take one of these different negative prefixes, and if you use the wrong negative prefix the word will sound off to a native speaker. Luckily, you will likely still be understood, because the negative connotation of all of these prefixes is the same – they all mean ‘not.’ But a native English speaker or other ESL speaker may look at you funny if you use the wrong prefix with the wrong word, because it will sound wrong. For learning to use the right negative prefix with the right word the best thing to do is practice, read, and listen to English as much as possible.

Another tricky thing about negative prefixes in English is that some root words can take more than one negative prefix, but the meaning of the word is then different, depending on the negative prefix used. This only happens in a minority of words, so you shouldn’t worry about it too much. When you come across these specific words, take note of them, and try to remember the specific meaning they have. Here are some examples:

disable – limited in movements, senses, or activities due to a disease or injury
unable – not having the skill or opportunity to do something

discomfort – a feeling of lack of comfort
uncomfortable – a physical feeling of slight pain

to discover – to find something out or become aware of something for the first time
to uncover – to remove a cover or top from something

In the end, what you need to remember is all the negative prefixes listed above mean ‘not’ when they are added to the front of a root word. The rest of the details will come with time as you use English on a regular basis.