THESAURUS
antipode, antipodes, antipole, antithesis, antonym, coequal, compeer, complement, contra, converse, coordinate, counter, counterbalance, countercheck, counterpart, counterpoint, counterpoise, counterpole, counterterm, cousin, ditto, equal, equipollent, equivalent, fellow, foil, inverse, like, match, mate, obverse, offset, opposite, parallel, peer, reverse, rival, setoff, tally, the contrary, the other side, twin, vis-a-vis