1.Definition: being sour to the taste

Related Adjective(s):acidic, acidulent, acidulous

2.Definition: harsh or corrosive in tone

"A barrage of acid comments"

Related Adjective(s):acerb, acerbic, acrid, bitter, blistering, caustic, sulfurous, sulphurous, virulent, vitriolic

3.Definition: having the characteristics of an acid

"An acid reaction"