The Collaborative International Dictionary of English v.0.48:

Pettish \Pet"tish\, a. [From Pet.]
   Fretful; peevish; moody; capricious; inclined to ill temper.
   "A pettish kind of humor." --Sterne. -- Pet"tish*ly, adv.
   -- Pet"tish*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

pettish
    adj 1: easily irritated or annoyed; "an incorrigibly fractious
           young man"; "not the least nettlesome of his countrymen"
           [syn: cranky, fractious, irritable, nettlesome,
           peevish, peckish, pettish, petulant, scratchy,
           testy, tetchy, techy]