Adjective acid-tongued (comparative more acid-tongued, superlative most acid-tongued) (possessional) Bitingly critical or sarcastic; sharp-tongued. 2016 February 7, Michael Barbaro, “Once Impervious, Marco Rubio Is Diminished by a Caustic Chris Christie”, in The New York Times:Mr. Christie then gave Mr. Rubio his trademark New Jersey treatment: He unleashed a series of rapid-fire, acid-tongued attacks on the man standing four podiums to his right, alternately looking directly at Mr. Rubio and at the camera.