Green’s Dictionary of Slang

(a) a cubby-hole, a small room.

1839		Congressional Globe 15 Feb. Appendix 343/1: We have a postmaster in our own little village [...] and in his little caboose of a post office I have found electioneering interferences [DA].
1873		Sl. Dict. 106: Caboose a term used by tramps to indicate a kitchen.
1910		Bulletin (Sydney) 11 Aug. 43/2: It was only a blind so that I could get the yellow stuff away in the billy. If I hadn’t built that new caboose they’d never have smelt even the rat I put through the drain to fix my string!
1912		Bulletin (Sydney) 14 Nov. 47/2: We scattered all the fiends of ’Ell; we let the Devil loose; / But Bill ’e was a credit to that spirit’ous caboose!
1915		M.G. Hayden ‘Terms Of Disparagement’ in DN IV:iii 203: caboose, any small place.
1916		C.J. Dennis ‘In Spadger’s Lane’ in Moods of Ginger Mick 71: Low down, a splotch o’ red, where ’angs a blind / Before the winder uv a Chow caboose.
1945		D. Bolster Roll On My Twelve 48: A ‘caboose,’ that is, a little hole, a store or an issue-room, is the thing for which every older rating yearns.
1996		L. Pettiway Honey, Honey, Miss Thang 223: My dad put me inside a caboose, and the caboose was full of rats.

(b) any form of place or room.

1861		Bell’s Life in Sydney 1 June 3/2: Polly, with affectionate solicitude, invited him to her caboose.
1874		Opelika Times 30 Sept. n.p.: A colored man [...] should be preferred as tenant of our houses, cabooses on the farm, drayman upon the streets [DA].
1895		Crowe Aus. Sl. Dict. 14: Caboose, a lodging-house.
1898		J.D. Brayshaw Slum Silhouettes 55: ‘And a very comfortable little caboose she’s got,’ said Bill.
1902		J. Masefield ‘A Night at Dago Tom’s’ in Salt-Water Ballads 38: We scooted south with a press of sail till we fetched to a caboose.
1916		J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 181: It’s got me wingin’, too. I keep right on workin’ — I lift a boob for $106.60 on a mainstem caboose yesterday.
1920		‘Sapper’ Bulldog Drummond 247: The mistake you’ve made [...] is not giving Peterson a seat in your Cabinet. He’d have the whole caboose eating out of his hand.
1924		C.J. Dennis ‘’Ave a ’Eart!’ in Rose of Spadgers 77: If I ’ad not cut loose / In Spadgers, in them days long, long deplored, / ’Ow could I knowed the run uv Foo’s caboose?
1936		(con. 1830s–60s) ‘Miles Franklin’ All That Swagger 149: Molly’s heart is scalded for ye, and if ye’r father will put up a little caboose for ye, Oi’ll set ye up rint free.
1953		A. Liddell Hart Strange Company 157: The large, blond German corporal in charge of the cook-house had also got a caboose inside the camp where he lived with his assistant .
1989		M. Amis London Fields 31: Lying in sleep’s caboose, seconds before Marmaduke woke him with a clout.

(c) a prison.

1825		C.M. Westmacott Eng. Spy II 217: May I be bolted into old Belzy’s caboose if she be a copper fastening the better for Jem Buntline!
1865		Leaves from Diary of Celebrated Burglar 29/1: While on the way to the ‘caboose’ Joe’s courage began to drop, for he saw but little chance of getting out of the scrape he was in.
1900		T.J. Hains Mr Trunnell Mate of the Ship ‘Pirate’ Ch. iii: ’Twould ha’ been no mutiny to override the new skipper, an’ land th’ other in th’ caboose.
1928		M. Bodenheim Georgie May 28: She’d land both of us in the caboose.
1939		Federal Writers Project These Are Our Lives 346: it’s going to be kept clean as long as I’m there if they put me in the caboose for cruelty to roaches and water bugs [DA].
1940		R. Chandler Farewell, My Lovely (1949) 14: Where you figure I been them eight years I said about? [...] In the caboose.
1953		Mad mag. June–July 22: Throw him in the caboose and report for your next assignment.
1960, 1975		Wentworth & Flexner DAS.
1970		K. Willey Naked Island 116: The policeman clicked on the handcuffs and escorted me ashore. I went into lodgings at the local caboose.

(d) in fig. use, penury; i.e. reduced to poor living circumstances.

1950

‘Hal Ellson’ Tomboy (1952) 95: Then you’d be broke [...] Right back in the caboose.

(a) the buttocks, the behind; occas. the back.

c.1919		in Winterich Mlle. from Armentières n.p.: She waggled her headlights and caboose.
1928		C. Panzram Journal of Murder in Gaddis & Long (2002) 24: He fell on his big fat caboose with his mouth wide open.
1929		A.J. Barr Let Tomorrow Come 41: He gives me one look an’ hauls his caboose back up to the stem.
1945		L. Hoban ‘Time to Kill’ Crack Detective Jan. 🌐 I bent over, turning the caboose to the blonde and the gat.
1956		N. Algren Walk on the Wild Side 25: You must be connected wit the railroads [...] you got such a perty caboose.
1969		‘Iceberg Slim’ Pimp 164: He drove his needle-toed shoe into her wide caboose.
1979		‘Iceberg Slim’ Airtight Willie and Me 44: He nearly tripped himself gazing at Sue’s caboose.
1980		P. Gable In Bondage Schoolgirl n.p.: ‘Yeah, baby, back it up, come on, move that fuckin’ caboose!’ Gino said, slapping her with both opened palms harder and harder while his groin slammed against her ass.
1987		‘Victoria Parker’ Pay for Play Cheerleaders 🌐 He cupped her teen-dream ass. [...] ‘Awwwww, shit!’ Chrissie cried. ‘He’s lickin’ my caboose!’.
1989–2003		R.O. Scott Gay Sl. Dict. 🌐.
1990		S. Morgan Homeboy 135: She’s got a sexy caboose.
2002		‘Teaser Pulls a Train’ at www.asstr.org 🌐 ‘Then the last guy gets the caboose.’ She didn’t understand that. ‘The last guy does you up the ass.’.

(b) a slow-witted person.

1924

Hecht & Bodenheim Cutie 40: For a few minutes this flat wheeled caboose of gloom couldn’t figure out which part of him was his feet.

(c) the last child in a family [also puns on SE papoose].

1950

in DARE.

(d) a person who continually follows along behind, a hanger-on.

1969

in DARE.

(e) (US campus) the last man in a session of group sex.

1969

in Current Sl. IV:3–4 (1970).