When you rub your knee against a woman's pussy. Cross between knee and shag.
Lad 1) mate how did you get on with your tinder date last night?

Lad 2) ah mate I just knag'd her
by Classic Bants October 15, 2017
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knag is gank in reverse. In essance it means to force somthing on sombody.
I got tired of carrying garbage around, so i knaged it to him.
by Justin October 24, 2004
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