Webster's Revised Unabridged Dictionary · 1913

Flaky

Flaky , adjective

1.
Consisting of flakes or of small, loose masses; lying, or cleaving off, in flakes or layers; flakelike.
What showers of mortal hail, what flaky fires! — Watts
A flaky weight of winter's purest snows. — Wordsworth
2.
prone to strange or erratic behavior; -- of persons.
3.
odd, unpredictable or unconventional; offbeat; whacky; -- of behavior.
4.
unpredictable, erratic, or unreliable; -- of machinery, especially electronic devices.
a flaky computer board.