Not safe for neighbours means that you're listening to House Music and turn up the sub and bass to adequately buzzing levels. This of course is not safe for neighbours and will be sure to piss them off.

NSFN means you will get a knock on the door to turn that racket down, but at least you won't be able to hear the door!
Just listen to that bass, turn up to max volume NSFN!
by Benny XI August 18, 2020
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