Green’s Dictionary of Slang

1. in vaudeville, slapstick comedy; also attrib.

1914		L.A. Times 17 Aug. III 2/4–5: The Howdy Special which annually makes the run across the desert to Phoenix at the time of the Phoenix road race, promises to be a record-breaking Jasbo party this year [...] Firestone Smith is a sure contender. John Weise has a great record for the Jasbo stuff, but A. T. Smith is out to break all records on the trip to Phoenix.
1915		N.Y. Times X2/5–6: The big laughs for jasbo, hokum, and gravy, as we call broad humor, frequently come from the women patrons in the house where it is performed.
1926		H.O. Osgood ‘Jazz’ in AS I:10 517: Mr. Kingsley ties them together by defining jasbo, as he spells it, as ‘a form of the word (jazz) common in the varieties, meaning the same as “hokum,” or low comedy verging on vulgarity’.

2. a black vaudeville performer, esp. in a ‘black and white minstrel’ show.

1920		Kansas City Sun (MO) 13 Nov. 2/3: ‘Hello Jazzbo’ briefly described is a high class colored musical organization of forty people, including a real creole beauty chorus and their own Jazzonian orchestra.
1922		Eve. World (NY) 19 Dec. 15/3: [advt] Jazzbo Jim; clogging toy, 50c. A very black boy who [...] when wound up dances a clog on the roof of a small log cabin.
1942		Berrey & Van Den Bark Amer. Thes. Sl. §583.18: Jazz-bo, jazzbo, a negro performer, esp. in a minstrel show.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 133: Like some jazzbo singing through his saxophone or trumpet or whatever.

3. syncopated music; also attrib.

1919		Noble Sissle ‘How Ya Gonna Keep ’Em Down on the Farm?’ 🎵 ’Cause I’m a jazz baby! / Full of jazzbo harmony!
1929		S. Ornitz Haunch Paunch and Jowl 150: Sam shouts in glee that he can twist a blareful, stirring Wagnerian fugue into nigger jazbo stuff.

4. a black person, esp. a man or soldier; also attrib.

1918		C. Sandburg ‘Singing Nigger’ Cornhuskers 🌐 Your bony head, Jazbo, O dock walloper, / Those grappling hooks, those wheelbarrow handlers, / The dome and the wings of you, nigger.
1935		D. Burley Chicago Defender 7 Dec. 17: The ‘Jazzbows’ had ‘Slick’ Shelby and Willie Jenkins as ace-men.
1939		Howsley Argot: Dict. of Und. Sl.
1944		Mencken ‘Designations for Colored Folk’ in AS XIX:3 174: The DAE does not list such vulgar synonyms for Negro as [...] jazzbo.
1957		Kerouac On The Road (1972) 109: He slowed down the car for all of us to turn and look at the old jazzbo moaning along.
1968		G. Cuomo Among Thieves 308: ‘Sure man,’ the nigger said, giving Orninski the big jazz-bo smile.
1978		W. Donaldson Balloons in Black Bag 90: If the Major calls him darky, [...] ape, jassbo, jigaboo, eightball, seal, jungle bunny, skunk or Zulu to his face, we’re going to be short of a valuable new comedy act.
1983		I.L. Allen Lang. of Ethnic Conflict 49: Other Cultural Allusions: jazzbo [19th century. Uncertain origin].

5. (US) a fellow, a man, esp. a fashionable young man.

1914		Edwardsville Intelligencer (IL) 10 Mar. 2/1: [cartoon caption] I knew a jasbo once who read that a chap getting paid $5,000 damages for being struck by an auto and thinking it was easy money he tried it.
1919		L.A. Times 2 Nov. III 42: When cornered on the subject of jazz fortunes ‘Frisco’ the prince of jazzbos, had something to say concerning the origin of the word [...].
1923		H.C. Witwer Fighting Blood 272: I merely commence to stutter a apology, when the old jazzbo shuts me off kind of angrily.
1937		E. Anderson Thieves Like Us (1999) 2: This is a stick-up, Jasbo.
1971		L. Bangs in Psychotic Reactions (1988) 64: As Ralph Jazzbo Gleason woulda said [...] ‘We made it. We won.’.
1993		I.L. Allen City in Sl. (1995) 69: This image is certainly evoked of a flapper dancing the Charleston, usually paired side-by-side with her jellybean, boyfriend, sheik, or jazz bo.

6. (US/US campus) a fool, an idiot; or something eccentric or crazy-looking [? bozo n.¹ (3)].

1929		H.C. Witwer Yes Man’s Land 309: That large blah [...] is sneering at the old man’s queer-looking jazzbo. ‘If you think I shall make an ass of myself by strutting before that idiotic contraption, you’re crazy!’.
1951		P. Whelton Angels are Painted Fair 78: You and this jazbo are all over the joint and you’re yelling he’s a stick-up guy.
1974		Eble Campus Sl. Mar. 3: jazzbo – a fool or idiot.