The Collaborative International Dictionary of English v.0.48:

Crabby \Crab"by\ (-b[y^]), a.
   Crabbed; difficult, or perplexing. "Persius is crabby,
   because ancient." --Marston.
   [1913 Webster]

WordNet (r) 3.0 (2006):

crabby
    adj 1: annoyed and irritable [syn: crabbed, crabby, cross,
           fussy, grouchy, grumpy, bad-tempered, ill-
           tempered]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "crabby":
   beefing, bellyaching, bitching, complaining, complaintful, crabbed,
   crabbing, cranky, croaking, disappointed, discontented,
   disgruntled, displeased, dissatisfied, dour, envious, faultfinding,
   gloomy, glum, griping, grouchy, grousing, growling, gruff,
   grumbling, grumbly, grumpish, grumpy, malcontent, malcontented,
   mumpish, murmuring, muttering, out of humor, peevish, petulant,
   querulant, querulous, rebellious, resentful, restive, restless,
   sulky, surly, unaccepting, unaccommodating, uneasy, unfulfilled,
   ungratified, unhappy, unsatisfied, whiny