alter ego

1 a person who has a strong liking for and trust in another over the years the state's other senator became his alter ego as well as his political ally Synonyms friend, amigo, buddy, chum, compadre, comrade, confidant, confidante, crony, familiar, intimate, mate [chiefly British], musketeer, palRelated Words acquaintance; associate, cohort, colleague, companion, fellow, hearty, hobnobber, partner, peer, sport; blood brother, brother, main man, sister; abettor (also abetter), accomplice, ally, collaborator, confederate; pen pal; benefactor, supporter, sympathizer, well-wisher; friendlyNear Antonyms adversary, antagonist, competitor, opponent, rival; archenemy, nemesisAntonyms enemy, foe

2 something or someone that strongly resembles another the hero of the novel is clearly the author's alter ego, right down to his receding hairline and middle-aged paunch Synonyms image, carbon, carbon copy, clone, counterpart, doppelgänger (or doppelganger), double, duplicate, duplication, facsimile, fetch, likeness, look-alike, match, mirror image, picture, replica, ringer, spit, spitting image, twinRelated Words Chinese copy; effigy, portrait, portrayal; companion, fellow, mate; equal, equivalent; analogue (or analog), parallelNear Antonyms antithesis, converse, opposite, reverse