acid

1 causing or characterized by the one of the four basic taste sensations that is produced chiefly by acids an acid-tasting medicine Synonyms sour, acidic, acidulous, sourish, tart, tartish, vinegaryRelated Words dry, soured, unsweetened; pungent, sharp, tangy, zestful, zesty, zingy; astringent, puckery hyperacidNear Antonyms sweet; bland, smooth; flat, flavorless, insipid, savorless, tasteless, zestless; dilute, thin, watery, weak

2 having or showing a habitually bad temper with her acid personality, my aunt could be relied upon to bring some much-needed balance to the holiday gush Synonyms ill-tempered, bearish, bilious, bloody-minded [chiefly British], cantankerous, disagreeable, dyspeptic, ill-humored, ill-natured, ornery, splenetic, surlyRelated Words choleric, crabby, cranky, crotchety, fussy, grouchy, grumpy, querulous; irascible, irritable, peevish, peppery, petulant, quick-tempered, short-tempered, snappish, snippy, testy, touchy; argumentative, contentious, contrary, cussed; angry, exasperated, indignant, irate, mad, upset, uptight; depressed, dour, glum, morose, sullen; anal, old-maidish, schoolmarmishNear Antonyms agreeable, amicable, congenial, friendly, pleasant; benign, gentle, kind, nice, sweet; bubbly, cheerful, cheery, effervescent, exuberant, high-spirited, joyful, lighthearted, lively, vivacious; content, glad, happy; calm, placid, serene; long-suffering, patient, tolerantAntonyms amiable, good-humored, good-natured, good-tempered

3 marked by the use of wit that is intended to cause hurt feelings a cultural gadfly known for an acid tongue that spares no one Synonyms acerb, acerbic, sarcastic, acidic, acidulous, acrid, barbed, biting, caustic, corrosive, cutting, mordant, pungent, sardonic, satiric (or satirical), scalding, scathing, sharp, smart-aleck, smart-alecky, smart-mouthed, snarky, tartRelated Words brisk, cross, sharp-tongued, sour, sourish, spiky (also spikey), tartish; incisive, keen, poignant, trenchant; cynical, dry, ironic (also ironical), wry; facetious, flippant, tongue-in-cheek; acrimonious, bitter, resentful, vitriolic; harsh, rough, severe, stringent; abrupt, blunt, brusque (also brusk), concise, crisp, curt, gruff, pithy, snippety, snippy, succinct, terse; backhanded, insincereNear Antonyms amusing, droll, merry, playful, sportive, waggish; gentle, mild; bland; good-humored, good-natured; diplomatic, polite, smooth, suave, urbane; affable, cordial, genial, gracious, hospitable, sociable