flak·y also flak·ey 
(flākē)
(flākē)adj. flak·i·er, flak·i·est
1. Made of or resembling flakes.
2. Forming or tending to form flakes or thin, crisp fragments: flaky pastry.
3. Slang
a. Undependable, as in keeping social engagements: a flaky friend who is always late.
b. Somewhat eccentric; odd: "that slightly flakey quality, in joy as well as in grief, that prepares us subtly for the mad scenes to come" (Village Voice).
flaki·ly adv.
flaki·ness n.