Green’s Dictionary of Slang

1. (orig. US) in pl., the ribs.

1895		Bee (Earlington, NY) 12 Sept. 4: I’ll give you a jolt in the slats. See?
1898		H.E. Hamblen General Manager’s Story 33: There’s nothing much the matter with him; few of his slats stove in, that’s all.
1900		A.H. Lewis ‘Red Mike’ in Sandburrs 59: Mike puts d’ boots to her an’ breaks t’ree of her slats.
1901		A. Binstead More Gal’s Gossip 71: First giving the spectators an exhibition of his splendid left by a series of visitations on Dick’s short slats.
1911		J. Masefield Everlasting Mercy 11: Billy bats / Some stinging short-arms in my slats.
1911		‘Sing Sing No. 57,700’ My View on Books in N.Y. Times Mag. 21 May 7/5: There’s a gum-shoe man in this that will make you feel like staving in his slats.
1922		H.L. Wilson Merton of the Movies 188: You can stoke up with meat and potatoes – anything you want that’ll stick to the merry old slats.
1924		G. Henderson Keys to Crookdom 417: Slats. A skinny person, the ribs.
1935		S. Kingsley Dead End Act II: Gimme two bits ’r I kick yuh ina slats.
1944		D. Runyon Runyon à la Carte 191: She cannot resist giving Cleo the calf a good kick in the slats.
1953		T.A.G. Hungerford Riverslake 214: Those silver-tails in the office get ideas if we don’t give ’em a kick in the slats occasionally.
1955		B. Appel Tough Guy [ebook] Scarey Cat, chase a rat; / Kick a jewboy inna slat.
1961		G.L. Coon Meanwhile, Back at the Front (1962) 43: A kick in the slats was the world’s best persuader.
1975		(con. 1900s) G. Swarthout Shootist 55: You talk tough t’me, you slatty sonabitch, I’ll part your hair on the other side.
1978		P. Theroux Picture Palace 303: Loved it, loved the revolution – that was a real kick in the slats.

2. (US short-order) in pl., spare-ribs.

1908

Commercial (Union City, TN) 22 May 5/1: ‘A bunch of slats.’ Spareribs.

3. (US, also slats) a thin person.

1907		T.A. Dorgan in Zwilling TAD Lex. (1993) 74: Sometimes, four or six got in, then, again, a fat guy would clog the passage, and then a squeak would be heard from some slat who was caught in the crush.
1924		G. Henderson Keys to Crookdom 417: Slats. A skinny person, the ribs.

4. (US prison) in pl., the steel mesh that covers the front of a prison cell.

1929		A.J. Barr Let Tomorrow Come 46: A man and a woman are outside the girl’s segment of the slats.
1992		Bentley & Corbett Prison Sl. 7: Grill also Cell Grill The barred or steel mesh front of a cell. (Archaic: slats).