From 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]