acerb, acerbate, acerbic, acid, acidic, acidulent, acidulous, acrimonious, acute, amaroidal, antagonistic, antipathetic, asperous, astringent, austere, belligerent, biting, bitter, bitter as gall, caustic, clashing, cloying, coarse, colliding, conflicting, corroding, corrosive, cutting, despiteful, double-edged, edged, escharotic, featheredged, fierce, fine, full of hate, hard, harsh, hateful, hostile, incisive, irritating, keen-edged, keen, knifelike, malevolent, malicious, malignant, mordacious, mordant, nose-tickling, oversweet, penetrating, piercing, piquant, poignant, pungent, quarrelsome, rancorous, razor-edged, repugnant, rigorous, rough, saccharine, scathing, scorching, set, set against, severe, sharp, sore, sour, spiteful, stabbing, stinging, strident, stringent, tart, trenchant, two-edged, vehement, venomous, violent, virulent, vitriolic, withering