Green’s Dictionary of Slang

bung n.1

also boung
[Frisian pung, purse]

1. [mid-16C–mid-19C] (UK Und., also bong) a purse.

2. [late 16C–mid-18C] a pocket.

3. [late 16C–mid-19C] a cut-purse.

4. [1950s+] a bribe.

5. [1990s+] a loan.

In compounds

bung-nipper (n.) (also boung-nipper, bung-tipper) [nipper n.1 (1)]

[mid-17C–mid-19C] (UK Und.) a cut-purse; a pickpocket.

In phrases

put the bung in (v.)

[1950s] to bribe, to hand over a bribe.