(a.) Caustic; bitter-tempered; sarcastic; as, acrimonious dispute, language, temper\.

acerb acerbate acerbic acid acidic acidulent acidulous acrid astringent belligerent biting bitter burning caustic choleric contentious corroding corrosive cranky cross cutting double-edged edged embittered escharotic fierce harsh incisive indignant irascible irate ireful keen mad mordacious mordant penetrating piercing poignant quarrelsome rancorous rankled resentful resenting rigorous rough scathing scorching severe sharp sore splenetic stabbing stewing stinging strident stringent tart testy trenchant vehement violent virulent vitriolic withering wrathful wrathy wroth