THESAURUS
opposite number
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