1 v lay (sexual). Usually refers to the act of intercourse itself, except when used by a bloke giving his mates the details about what happened with that tidy bird he pulled in the club the night before. In this case, the term shag should be interpreted to mean anything between a peck on the cheek and a punch in the face. Brits find very amusing the use of the word “shag” in the U.S. to refer to certain dances. 2 adj shagged tired. In much the same way as most other humping words can be used: Spent the whole day hiking and now I’m completely shagged.