The quality of being oppositive.

plural of oppositive

(childish) A contrived holiday on which everything is done backwards, for example "yes" means "no".

(idiomatic) A person who holds a position in an organization that corresponds to that held by another person in another organization; a counterpart

A side, party (e.g. a team or armed force) seen as adversary, enemy etc. opposite one (or more) other(s), as in a battle or team sports competition.

plural of opposite number

Women in relation to men or men in relation to women. / (attributively) Heterosexual, or otherwise relating to a relationship between a woman and a man.

People who are completely different make ideal partners.

plural of opposite side

The complete opposite, opposite in every way.