We don't have any synonyms for opposite side yet.
Think opposite side belongs in the thesaurus? Recommend it and we'll take a look.
Definition of opposite side:
(n) :
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.
(n) :
The side (or more specifically, leg) of a right triangle that is opposite (or not adjacent to) a given angle.