c.1330, possibly from O.E.
*flacca "flakes of snow," from O.N.
flak "loose or torn piece" (related to O.N.
fla "to skin," see
flay), from P.Gmc.
*flak- (cf. M.Du.
vlac "flat, level," M.H.G.
vlach, Ger.
Flocke "flake"); from the same PIE root as L.
plaga "a flat surface, district, region."
Flaky "eccentric, crazy" first recorded 1959, said to be Amer.Eng. baseball slang, but probably from earlier druggie slang
flake "cocaine" (1920s).
Flake "eccentric person" is a 1968 back-formation from
flaky."The term 'flake' needs explanation. It's an insider's word, used throughout baseball, usually as an adjective; someone is considered 'flaky.' It does not mean anything so crude as 'crazy,' but it's well beyond 'screwball' and far off to the side of 'eccentric.' " ["New York Times," April 26, 1964]