Green’s Dictionary of Slang

1. to force a door or window.

1984

Partridge DSUE (8th edn).

2. (orig. milit.) to hit, to beat up, to defeat.

1984		Partridge DSUE (8th edn).
1999		J. Cameron Brown Bread in Wengen [ebook] [Y]ou say it never was the family banjo’d your Oliver.
2009		T. Black Gutted 123: How long will it be before I’m locked up for banjoing someone.
2012		(con. 1980s) I. Welsh Skagboys 332: Each too embarrassed tae be seen tae be the yin banjoing this midget.

3. to have sexual intercourse.

2018

I. Welsh Dead Man’s Trousers [15]: Rode the mother-in-law, the wee sister, banjoed the fucking maid of honour on the night before the wedding; the whole shebang.