Definition:
USE:
An antonym is a word that means the opposite of another.
eg: 'fat' is an antonym of 'thin'
More examples of antonyms:
Antonyms made by adding the prefix un-
likely / unlikely
able / unable
fortunate / unfortunate
Antonyms made by adding the prefix non-
entity / nonentity
conformist / nonconformist
Antonyms made by adding the prefix in-
tolerant / intolerant
discreet / indiscreet
decent / indecent