The Collaborative International Dictionary of English v.0.48:

Techy \Tech"y\, a. [From OE. tecche, tache, a habit, bad habit,
   vice, OF. tache, teche, a spot, stain, blemish, habit, vice,
   F. tache a spot, blemish; probably akin to E. tack a small
   nail. See Tack a small nail, and cf. Touchy.]
   Peevish; fretful; irritable.
   [1913 Webster]

WordNet (r) 3.0 (2006):

techy
    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]