acid acid /ˈæsɪd/

adjective

1. () Harsh or corrosive in tone  ( acerb , acerbic , acrid , acid , caustic , sulfurous [ N. American] , sulphurous [Canadian, British] , virulent , vitriolic , bitter , blistering )
   harsh or corrosive in tone
    An acerbic tone piercing otherwise flowery prose
   an acerbic tone piercing otherwise flowery prose
    A barrage of acid comments
   a barrage of acid comments
    Her acrid remarks make her many enemies
   her acrid remarks make her many enemies
    Bitter words
   bitter words
    Blistering criticism
   blistering criticism
    Caustic jokes about political assassination, talk-show hosts and medical ethics
   caustic jokes about political assassination, talk-show hosts and medical ethics
    A sulfurous denunciation
   a sulfurous denunciation
    A vitriolic critique
   a vitriolic critique
   
2. (chemistry) having the characteristics of an acid  ( acid )
   (chemistry) having the characteristics of an acid
    An acid reaction
   an acid reaction
   
3. Being sour to the taste  ( acid , acidic , acidulent , acidulous )
   being sour to the taste
   

noun

1. () 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  ( acid )
   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
     The scientist added a few drops of acid to the solution to lower its pH.
   The scientist added a few drops of acid to the solution to lower its pH.
   
2. Street name for lysergic acid diethylamide  ( acid , back breaker [Slang] , battery-acid [Slang] , dose [Slang] , dot , Elvis [Slang] , loony toons [Slang] , Lucy in the sky with diamonds [Slang] , pane [Slang] , superman [Slang] , window pane [Slang] , Zen )
   street name for lysergic acid diethylamide