How to Make Opposite Words Using Prefixes In English, we can often change the meaning of a word to its opposite by adding a prefix. A prefix is a group of letters added before a word. Common prefixes used to form opposites are: un- (e.g., unhappy) in-, im-, il-, ir- (e.g., incorrect, impossible, illegal, irregular) dis- (e.g., disagree) non- (e.g., nonverbal) Let's look at each word and make its opposite by adding a suitable prefix. Then, we'll see three more examples using the same prefix pattern. (a) Comfortable → Uncomfortable Prefix used: un- Meaning: Not comfortable More examples: Happy → Unhappy Fair → Unfair Safe → Unsafe (b) Necessary → Unnecessary Prefix used: un- Meaning: Not necessary More examples: Wanted → Unwanted Known → Unknown Clear → Unclear (c) Like → Dislike Prefix used: dis- Meaning: To not like More examples: Agree → Disagree Appear → Disappear Connect → Disconnect (d) Valid → Invalid Prefix used: in- Meaning: Not valid More examples: Active → Inactive Complete → Incomplete Visible → Invisible (e) Regard → Disregard Prefix used: dis- Meaning: To have no regard or concern More examples: Obey → Disobey Trust → Distrust Approve → Disapprove