acerb, acerbate, acescent, acetose, acid, acidic, acidulent, acidulous, acrid, acrimonious, amaroidal, asperous, astringent, biting, bitter, bitter as gall, burning, caustic, choleric, coarse, corroding, corrosive, crab, crabbed, cutting, dry, embittered, escharotic, green, hard, harsh, incisive, irritating, keen, mordacious, mordant, nose-tickling, penetrating, pickled, piercing, piquant, poignant, pungent, rancorous, rankled, resentful, resenting, rough, scathing, scorching, sec, severe, sharp, sore, sour, sour as vinegar, soured, sourish, splenetic, stabbing, stewing, stinging, tart, tartish, trenchant, unripe, unsweet, unsweetened, vinegarish, vinegary, virulent, vitriolic, withering