acid

(noun) any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt.

(noun) street name for lysergic acid diethylamide. Synonyms: back breaker, battery-acid, dose, dot, Elvis, loony toons, Lucy in the sky with diamonds, pane, superman, window pane, Zen.

(adj) harsh or corrosive in tone. Synonyms: acerb, acerbic, acrid, bitter, blistering, caustic, sulfurous, sulphurous, virulent, vitriolic. Examples: "An acerbic tone piercing otherwise flowery prose." "A barrage of acid comments." "Her acrid remarks make her many enemies." "Bitter words." "Blistering criticism." "Caustic jokes about political assassination, talk-show hosts and medical ethics." "A sulfurous denunciation." "A vitriolic critique."

(adj) being sour to the taste. Synonyms: acidic, acidulent, acidulous.

(adj) having the characteristics of an acid. Example: "An acid reaction."