Synonyms of indifferent

1 Syllable
numb, stoic, p, neb, lax, cold, blasé, cool
2 Syllables
stony, offish, blase, wearier, haughty, thoughtless, heedless, so-so, aloof, fairish, highbrow, lazy, torpid, distant, laziest, neutral, scornful, tepid, languid, laxer, lazier, haughtier, stonier, weary, remiss, stretchy, stoical, mopish, zipper, silent, halfway, withdrawn, snoozy, middling, low-rent, soso, weariest, listless, cold-fish, stolid, callous, heartless
3 Syllables
half-hearted, pitiless, low-ranking, unmoved, standoffish, unstirred, free-wheeling, hardhearted, unhearing, unthoughtful, hot-headed, neglectful, iceberg, unpitying, defaultant, unsocial, incurious, unbiased, uncurious, bone-tired, whitebread, nonchalant, toplofty, stuporous, asocial, ungenial, bystanding, unwatchful, halfhearted, white-bread, impervious, detached, passionless, disdainful, superior, untouched, languorous, impartial, cold-hearted, unloving, uncaring, sleepyhead, phlegmatic, unready, regardless, lymphatic, slow-moving, mediocre, low-grade, second-class, lethargic, passive, spiritless, careless, diffident
4 Syllables
perfunctory, unimportant, uninfluenced, unexcited, aversive, disenthralled, disentranced, apathetic, impersonal, unconcerned, unobserving, unperceiving, tolerable, impassive, non-combatant, uninvolved, middle-of-road, uninspired, unaroused, unimpressed, unbothered, nonspecific, objective, unlively, unpassioned, supercilious, disaffected, noncombatant, equitable, emotionless, case-hardened, unindustrious, undeceived, low-quality, disenchanted, nonresistant, nonpartisan, nonaligned, transitional, undiscerning, impassible
5 Syllables
unenthusiastic, uninterested, unemotional, unresponsive, unimpressible, unsympathetic, casehardened, disillusioned, inattentive, unexcitable, garden-variety, intermediate, inexcitable, nonemotional, nonbelligerent, middle-of-the-road, unremarkable, unnoteworthy, unsubmissive, unaffiliated, disinterested, unenergetic, disimpassioned, dispassionate, hebetudinous, unprejudiced, unmotivated, pococurante
6 Syllables
uncompassionate, undemonstrative, nonparticipating
7 Syllables
uncommunicative