(a.) Slightly sour; sub-acid; sourish; as, an acidulous tincture.

acerb acerbate acerbic acetic acetose acetous acid acidic acidulated acidulent acrid acrimonious astringent biting bitter burning caustic choleric corroding corrosive cutting double-edged dry edged embittered escharotic fierce harsh hyperacid incisive keen mordacious mordant penetrating piercing piquant poignant pungent rancorous rankled resentful resenting rigorous rough scathing scorching severe sharp sore splenetic stabbing stewing stinging strident stringent subacid subacidulous tart trenchant vehement violent virulent vitriolic withering