bunk-up noun 2bunk up verb 2forms 4 noun2 •(UK, informal) A manoeuvre in which one person is pushed upwards by another, or others, in order to climb over a fence or similar obstacle.Give us a bunk-up and I'll get your ball back. •(slang) Casual sex.You don't feel like a bit of a bunk-up this evening, Stubby, by any chance? — 1971 bunk up verb2 •(informal) To sleep in the same house, room or bed as someone else.I have to bunk up with Joel, as my landlord has kicked me out. •(slang) To have sex. formsbunked up · bunking up · bunks up · bunk-ups