flaky, adj. — Green’s Dictionary of Slang

flaky adj.

also flakey, flako

[orig. baseball use. ‘It’s an insider’s word...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, 26 April 1964; ? SE fall/crumble into flakes, i.e. to come apart]

(orig. US)

1. of a person, second-rate, unreliable, distasteful, eccentric, crazy.

1959		Baseball Digest XVIII:2 52/1: Flakey: origin is unknown, but it has replaced wacky, squirrely and the like in the ‘inside’ vocabulary.
1967		N.Y. Times 31 Mar. 42: Andy is a great guy to room with. He’s flaky of course, but not quite as crazy as I am.
1973		Manchester Guardian Weekly 13 Oct. 19: An officer might handle vast sums of money, the temptations were enormous, and there was some flakey behaviour.
1977		C. McFadden Serial 23: Carol, Kate’s flaky friend from her consciousness-raising group.
1980		Jackson & Christian Death Row 45: Because they’re flaky, you know, just strange.
1999		Guardian G2 28 June 8: There is an assumption that beautiful women are too flaky [...] to reach the top.
2004		C. Hiaasen Skinny Dip 73: The flaky Aussie who wrestles crocodiles on TV.
2005		L. Theroux Call of the Weird (2006) 63: People are ‘flaky’.
2013		T. Robinson Hard Bounce [ebook] ‘Cassie’s a cool chick and all, but she’s a little flaky’.
2022		J. Hannaham Didn’t Nobody Give a Shit 124: As if he hadn't acted flaky enough, Boz showed her his back and then started talking to her.

2. of an object, eccentric, crazy, outrageous, unusual, unreliable or erratic.

1966		Coshocton (OH) Trib. 15 Mar. 4/4–5: Sometimes our parents have a cow about our slang, but heck, life would be flaky without it. Don’t you think?
1977		A. Brooke Last Toke 156: Money up the ass from that flako joint he owns.
1978		P. Theroux Picture Palace 37: Flaky. Sometimes they’re the best kind.
1978		S. King Stand (1990) 972: Things are going to get flaky without it.
1999		Indep. Traveller 21 Aug. 5: Absurdly flakey and idealistic? Not entirely.

In derivatives

flakiness (n.)

the quality of being unreliable, eccentric.

1976		A. Sklar Runaway Wives 169: Cathy still worries about her flakiness. Amy sits in a rented room struggling to do something, anything.
1977		E. Asinof Say It Ain’t So, Gordon Littlefield 170: He was a brilliant cornerback with the instincts of a great athlete, but I was put off by his flakiness.
1982		J. Jerome Sweet Spot in Time 309: Dwight Stones, who for all his flakiness probably does know as much about the high jump as any athlete, was a TV commentator.
1992		R. Ebert Ebert’s Home movie Companion 124: He is also, Eddie observes, a ‘flake,’ and that gives him an idea: [...] this kid could be steered into the world of big-money pool, where his flakiness would throw off the other players.
2001		C. Stella Eddie’s World 4: We got along. I liked her flakiness. [Ibid.] 31: The flakiness that had originally attracted Eddie to Diane had become too unpredictable.