flaky

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Made of or resembling flakes.
• adjective Forming or tending to form flakes or thin, crisp fragments.
• adjective Slang Somewhat eccentric; odd.

from The Century Dictionary.

• Consisting of flakes or locks; lying or cleaving off in flakes or layers; flake-like.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Consisting of flakes or of small, loose masses; lying, or cleaving off, in flakes or layers; flakelike.
• adjective prone to strange or erratic behavior; -- of persons.
• adjective odd, unpredictable or unconventional; offbeat; whacky; -- of behavior.
• adjective unpredictable, erratic, or unreliable; -- of machinery, especially electronic devices.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Consisting of flakes or of small, loose masses; lying, or cleaving off, in flakes or layers; flakelike.
• adjective informal, of a person Unreliable; prone to make plans with others but then abandon those plans.
• adjective informal, of a thing Unreliable; working only on an intermittent basis; prone to cease functioning properly.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective conspicuously or grossly unconventional or unusual
• adjective made of or easily forming flakes
• adjective made of or resembling flakes