[syn: acerb, acerbic, acid, acrid, bitter, blistering, caustic, sulfurous, sulphurous, virulent, vitriolic]
The Collaborative International Dictionary of English v.0.48:
Acrid \Ac"rid\, a. [L. acer sharp; prob. assimilated in form to
   acid. See Eager.]
   1. Sharp and harsh, or bitter and not, to the taste; pungent;
      as, acrid salts.
      [1913 Webster]
   2. Causing heat and irritation; corrosive; as, acrid
      secretions.
      [1913 Webster]
   3. Caustic; bitter; bitterly irritating; as, acrid temper,
      mind, writing.
      [1913 Webster]
   Acrid poison, a poison which irritates, corrodes, or burns
      the parts to which it is applied.
      [1913 Webster] Acridity
WordNet (r) 3.0 (2006):
acrid
    adj 1: strong and sharp;"the pungent taste of radishes"; "the
           acrid smell of burning rubber" [syn: pungent, acrid]
    2: harsh or corrosive in tone; "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" [syn:
       acerb, acerbic, acid, acrid, bitter, blistering,
       caustic, sulfurous, sulphurous, virulent,
       vitriolic]
Moby Thesaurus II by Grady Ward, 1.0:
86 Moby Thesaurus words for "acrid":
   acerb, acerbate, acerbic, acid, acidic, acidulent, acidulous,
   acrimonious, acute, amaroidal, antagonistic, antipathetic,
   asperous, astringent, austere, belligerent, biting, bitter,
   bitter as gall, caustic, clashing, cloying, coarse, colliding,
   conflicting, corroding, corrosive, cutting, despiteful,
   double-edged, edged, escharotic, featheredged, fierce, fine,
   full of hate, hard, harsh, hateful, hostile, incisive, irritating,
   keen, keen-edged, knifelike, malevolent, malicious, malignant,
   mordacious, mordant, nose-tickling, oversweet, penetrating,
   piercing, piquant, poignant, pungent, quarrelsome, rancorous,
   razor-edged, repugnant, rigorous, rough, saccharine, scathing,
   scorching, set, set against, severe, sharp, sore, sour, spiteful,
   stabbing, stinging, strident, stringent, tart, trenchant,
   two-edged, vehement, venomous, violent, virulent, vitriolic,
   withering