Green’s Dictionary of Slang

1. (also beau, boh) a fellow, a man, a friend, often as a form of address, e.g. Hey, bo.

1825		W.N. Glascock Naval Sketch-Bk (1826) I 148: Small helm bo – steady-ey-a.
1867		W.H. Smyth Sailor’s Word-Bk (1991) 111: Bo. Abbreviation of boy. A familiar epithet for a comrade, derived probably from the negro.
1874		M. Clarke Term of His Natural Life (1897) 37: ‘Half a gallon a day, bo’, and no more,’ says a sailor next to him.
1884		Henley & Stevenson Admiral Guinea III ii: See here, my bo, if you’ve the pluck of a weevil in a biscuit, this girl is yours.
c.1895		The Standard Quartette [song title] So, Bo, Give Me Them Two Bits.
1905		H. Green Actors’ Boarding House (1906) 13: Aw, come off; that’s a Broadway salary, bo.
1916		J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 157: Breathing the dirty air of his native metropolis again, was glad to be home—glad to be home, bo.
1928		C. McKay Home to Harlem 19: Tha’s some stuff you’re strutting in, boh.
1929		D. Hammett ‘Fly Paper’ Story Omnibus (1966) 55: You sure devastated me, bo.
1939		V. Davis Gentlemen of the Broad Arrows 13: Ah got nine months, bo’.
1940		E. Curry Hysterical Hist. of Aus. 40: What I’m gonna point out to you, bo, is this: These boys are air hot members.
1954		N.Y. Herald Trib. 28 Feb. 47/1: ‘Hey, beau’ is used by boys for addressing each other.
1957		Kerouac On The Road (1972) 64: Say, bo, what was all the noise around here last night?
1963		L. Daiken Out Goes She 35: Old Jo he was a bo. R.I.P.
1971		E. Bullins ‘Dandy’ in King Black Short Story Anthol. (1972) 82: Well, it’s like dis, Bo.
1978		D. DeLillo Running Dog (1992) 185: Hey, bo, come on down.
1988		S. Selvon Eldorado West One 58: Thanks, bo...
2011		(con. late 1930s) H. Ellison Introduction in Pulling a Train’ [ebook] Sharing gypsy coffee with [...] hobos, and we called each other brother—or just ’bo.

2. (Aus./US, also bow) a vagrant, a tramp.

1893		Chicago Record 14 July 11/3: An’ den w’en ye meets one uv yer own kind ye feels like old pals, ’cause he calls ye ‘Ho’ an’ ye calls him ‘Bo’. See? [DA].
1899		J. Flynt Tramping with Tramps 388: He cautioned me not to say anything to the ‘boes’ (hoboes) about his being my ‘meal-ticket’.
1907		J. London Road 120: From some bo on the drag I managed to learn what time a certain freight pulled out. I calculated my time accordingly.
1910		H.E. Lee ‘Tough Luck’ Variety Stage Eng. Plays 🌐 The only chance for a bow to hit a bunch of joy purchasers here is to bet on the gee-dee-ups then bet the bookies you’ll lose.
1913		Day Book (Chicago) 10 Dec. 4/2: You are [...] forced to tell the history of your life, how you got to be a ‘bo’ .
1923		N. Anderson Hobo 6: It is a favourite place for the ‘bos’ to sleep in summer or to enjoy their leisure, relating their adventures and reading the papers.
1935		N. Algren ‘If You Must Use Profanity’ in Texas Stories (1995) 46: He’ll be walking the tops and be dressed like a ’bo, so you’ll never know by his looks he’s a bull.
1944		in A. Marshall These Are My People (1957) 145: I pulled up a bo and asked him if he knew where I could get a hand-out.
1953		J. Thompson Savage Night (1991) 107: Taking on the boes for a dime or a nickel or a cart of coffee.
1964		B. Jackson Get Your Ass in the Water (1974) 133: When I first come to New Orleans I was a ’bo hopped off a jolt.
1967		K. Tennant Tell Morning This 394: ‘We used to camp out [...] Just a bunch of ’boes’.
1991		O.D. Brooks Legs 2: A bum that won’t rustle food for himself [...] is scorned by the bos that hustle for themselves.
2000		Sun. Times Mag. 6 Feb. 27: The hard worker who [...] kept the jungles [railside camps] clean, shared what he had with his fellow ’bos.

3. attrib. use of sense 2.

1931

Irwin Amer. Tramp and Und. Sl. 32: Bo Cave.—A shack or hut where tramps congregate, usually near a railroad yard or water tank, where trains may be boarded. [Ibid.] 33: Bo Park.—A jocular term for any railroad yard around which tramps and hobos congregate while waiting for a train on which to leave town.

4. (US) a tramp’s young homosexual companion; thus a young, effeminate male homosexual.

1918		H. Simon ‘Prison Dict.’ in AS VIII:3 (1933) 24/2: BO. [...] 2. Boy, catamite.
1966		Trimble 5000 Adult Sex Words and Phrases 28: bo (Sl.) n. A Homosexual youth; a Catamite.
1972		B. Rodgers Queens’ Vernacular 107: Hobo slang (kwn ’30s & ’40s) [...] The adolescent who usually doubled as cook/lover to a homosexual hobo was called a [...] bo.
1986–7		Maledicta IX 145: Special terms not much known outside male prostitute circles include […] belle and bo (the latter pair more effeminate benders).