List of sullen synonyms and sullen related words.
antisocial, at odds, autistic, averse, bad-tempered, balking, balky, bashful, beetle-browed, bigoted, black, black-browed, brooding, broody, bulldogged, bulletheaded, bullheaded, cantankerous, case-hardened, chapfallen, choleric, churlish, close, contrary, crabbed, crabby, cranky, crestfallen, cross, cross-grained, crotchety, crusty, cursory, cynical, dark, dejected, depressed, depressing, differing, difficult, disagreeing, disinclined, dismal, disobedient, dissociable, dogged, dogmatic, dour, dreary, dumpish, dyspeptic, fanatic, forced, fractious, fretful, froward, frowning, funereal, gloomy, glowering, glum, grim, grum, grumpy, hardheaded, headstrong, hostile, ill-humored, ill-natured, ill-tempered, incompatible, indisposed, indocile, insociable, intolerant, involuntary, irascible, long-faced, lowering, lugubrious, malevolent, malicious, malign, mean, melancholy, moodish, moody, mopey, moping, mopish, morose, mulish, mumpish, mutinous, nongregarious, obstinate, opinionated, opposed, ornery, out of humor, out of sorts, overzealous, peevish, perfunctory, persevering, pertinacious, perverse, pessimistic, petulant, pigheaded, pouting, recalcitrant, refractory, resistant, restive, runty, saturnine, scowling, self-contained, self-sufficient, self-willed, set, snug, socially incompatible, sour, splenetic, stiff-necked, strong-willed, strongheaded, stubborn, stuffy, sulking, sulky, surly, temperamental, tenacious, tenebrose, tenebrous, ugly, unclubbable, uncommunicative, uncompanionable, uncongenial, unconsenting, uncooperative, unfriendly, ungenial, unregenerate, unsociable, unsocial, unwilling, wayward, willful, wrongheaded