A variation of the word antonym, in a manner similar to the way synonym and synonymous are related. When several words are synonyms, they mean approximately the same thing. However, when they are synonymous, they mean exactly the same thing. Similarly, there must be a word that means exactly opposite, to pair with "antonym" which only means approximately opposite. Thus, antonymous words are words that are exact polar opposites in meaning.

A word that has an opposite meaning to another word.

A word that means the opposite of another word.

The exact opposite of;

Means the same as opposite. Antonym and opposite are both synonyms.

used when you are talking about your aunt and the people she lives or hangs around with

the opposite of your personality