Green’s Dictionary of Slang

lump and bump n.

[rhy. sl. = chump n. (2)]

a fool, a simpleton.

[UK]P. Allingham Cheapjack 64: I don’t want wide people [...] It’s the greedy, half-baked lumps-and-bumps I’m after.
[UK]B. Kirkpatrick Wicked Cockney Rhy. Sl.