old chap

plural old chaps

1. UKdatedAffectionate term of address for a man.

   ‘Well, look here, old chap,’ he said, ‘let's have strict business between friends. If you'll pay me back four quid at the end of term, you shall have the two pounds. How does that strike you?’

   1903, P. G. Wodehouse, A Prefect's Uncle, A & C Black

   Synonyms: old fellow

2. UKcolloquialThe penis.

   1997-99, various writers, Blue Jam DR PERLIN: I'll need to have a look at your old chap.

   1 more example

   Withnail: You fill this with piss, take this pipe down the trouser, and sellotape this valve to the end of the old chap. Then you get horribly drunk, and they can't fucking touch you.

   1987, Bruce Robinson, Withnail and I

   Synonyms: old fellow