The Collaborative International Dictionary of English v.0.48:

Cantankerous \Can*tan"ker*ous\, a.
   Perverse; contentious; ugly; malicious. [Colloq.] --
   Can*tan"ker*ous*ly, adv. -- Can*tan"ker*ous*ness, n.
   [1913 Webster]

         The cantankerous old maiden aunt.        --Thackeray.
   [1913 Webster] Cantar

WordNet (r) 3.0 (2006):

cantankerous
    adj 1: stubbornly obstructive and unwilling to cooperate;
           "unions...have never been as bloody-minded about
           demarcation as the shipbuilders"- Spectator [syn:
           bloody-minded, cantankerous]
    2: having a difficult and contrary disposition; "a cantankerous
       and venomous-tongued old lady"- Dorothy Sayers [syn:
       cantankerous, crotchety, ornery]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "cantankerous":
   bad-tempered, bearish, bilious, bitchy, cankered, choleric,
   churlish, contrary, crabbed, crabby, cranky, cross, cross-grained,
   crotchety, crusty, cussed, difficult, disagreeable, dour,
   dyspeptic, excitable, feisty, fractious, froward, grouchy, grumpy,
   huffish, huffy, ill-conditioned, ill-natured, ill-tempered,
   irascible, irritable, liverish, mean, morose, ornery, peevish,
   perverse, petulant, prickly, quarrelsome, snappish, sour, spiteful,
   spleeny, splenetic, stuffy, sulky, sullen, surly, testy, tetchy,
   touchy, ugly, vinegarish, vinegary, waspish, wayward,
   wrongheaded