PLUNGE Copy link • PLUNGE 1. v. TRANS., mergere in aquam aliquid (Cic.); intingere in aqua (Vitr.). INTRANS., se mergere or immergere; mergi; immergi (Cic.); mersari (to plunder repeatedly, Hor., Ep.). 2. s. Act of plunging, by the verbs (immersio, Arnobius). Distress, angustia, difficultas.