WordWeb Online

1. Harsh or corrosive in tone
   "a vitriolic critique";
   - acerb, acerbic, acid, acrid, bitter, blistering, caustic, sulfurous [N. Amer], sulphurous [Brit, Cdn], virulent, acidulous, sulphureous [Brit]
    
2. Of a substance, especially a strong acid; capable of destroying or eating away by chemical action
   - caustic, corrosive, erosive, mordant

See also: destructive, unpleasant

Encyclopedia: Vitriolic