List of equivalent synonyms and equivalent related words.
Doppelganger, accordant, actual thing, affirmative, agent, agnate, agreeable, agreeing, akin, alike, all one, all the same, ally, alter ego, alternate, alternative, analogon, analogous, analogue, analogy, answerable, answering, associate, at one, backup, balance, ballast, brother, carbon copy, change, changeable, changeling, close, close copy, close match, coequal, coexistent, coexisting, coextensive, cognate, coherent, coincident, coincidental, coinciding, commensurate, commutable, commutative, companion, comparable, comparison, compatible, compeer, complement, complemental, complementary, concordant, concurring, conformable, congenator, congener, congenial, congruent, congruous, consentaneous, consentient, consideration, consistent, consonant, convertible, cooperating, cooperative, coordinate, copy, correlate, correlative, correspondent, corresponding, coterminous, counterbalance, counterfeit, counterpart, counterpoise, counterweight, dead ringer, deputy, ditto, double, dummy, duplicate, en rapport, equal, equalizing, equiparant, equipoise, equipollent, ersatz, even, exact counterpart, exchange, exchanged, facsimile, fake, fellow, fill-in, ghost, ghostwriter, give-and-take, harmonious, homograph, homologous, homonym, homophone, idem, identic, identical, identical same, image, imitation, in accord, in agreement, in rapport, in sync, in synchronization, inaccordance, indistinguishable, inharmony, interchangeable, interchanged, kindred spirit, like, like-minded, likeness, locum tenens, makeshift, makeweight, match, matching, mate, metaphor, metonymy, mock, much the same, mutual, near duplicate, next best thing, no other, none other, obverse, of a kind, of a piece, of a size, of like mind, of one mind, offset, on all fours, opposite number, parallel, paralleling, peer, pendant, permutable, personnel, phony, picture, pinch, pinch hitter, positive, proportionate, provisional, proxy, quid pro quo, reciprocal, reciprocating, reciprocative, reconcilable, relief, replacement, replica, representative, reserve, reserves, retaliatory, returnable, ringer, rival, second self, second string, secondary, self-consistent, selfsame, setoff, sign, similar, similitude, simulacrum, sister, something of value, soul mate, spare, spares, spit and image, spitting image, stand-in, standard, stopgap, sub, substituent, substitute, substitution, succedaneum, such, suchlike, superseder, supplanter, surrogate, swapped, switched, symbiotic, symbol, synchronized, synchronous, synecdoche, synonym, synonymous, tally, tantamount, temporary, tentative, the like of, the likes of, the same, the same difference, third string, tit for tat, token, traded, transposed, twin, unanimous, understudy, undifferenced, uniform, unisonant, unisonous, utility, utility player, very image, very same, vicar, vicarious, vice-president, vice-regent