Green’s Dictionary of Slang

bumming n.

[bum v.3 (4)]

1. (US campus) living as an idler or loafer.

[US]Yale Literary Mag. XXV 308: Another great shame connected with our social life is that of spreeing or ‘bumming’ [DA].
[US]J.D. McCabe Lights & Shadows 682: [H]e readily admits that ‘Bumming’ is a hard life, but he is confident that it is better than working for a living.
[Aus]Bird o’ Freedom (Sydney) 28 Mar. 4/3: Can Anybody Tell Us [...] How much ‘bumming’ a pro can do when he is really put to it?
[US]E. Booth Stealing Through Life 152: Just bumming around gets awfully tiresome.

2. (US) living as a vagrant tramp or hobo.

[US]S.F. Call 9 Jan. 1/2: The ‘Bumming and Gassing Company’ were out in full strength, the novelty of labor being a new experience [DA].
[US]Appleton’s Journal (N.Y.) 30 Apr. 497/1: It could be no worse than ‘bumming,’ i.e., sleeping out.
[UK]C. Roberts Adrift in America 66: The idea of begging, or ‘bumming,’ as it is popularly called out there, went strongly against my stomach.
[US]J. Flynt Tramping with Tramps 137: It ain’t work that makes blokes hungry; it’s bummin’!
[US]‘A-No. 1’ Snare of the Road 11: The job I made of box car bumming proved so eventless.
[US]N. Algren ‘A Place to Lie Down’ in Texas Stories (1995) 58: Bummin’ takes all the tallow out o’ mah pole.

3. (US campus) relaxing.

[US]Da Bomb 🌐 5: Bummin’: Staying at home, relaxing.

4. (US teen) dressing unfashionably.

[US]Springfield (MA) Union-News 9 Sept. C6/5–6: bummin’—To dress in a very tacky way.