Numpft

It is commonly used to describe a person who is a bit on the slow side of things and has a general delayed reaction to most subjects ,especially humour. It originates from the word numpfty

In reality the word actually doesn’t seem that offensive and sort of sounds like something your nan or partner would call you if you were acting the ejet i.e falling down a flight of stairs

Victim: *clips ankle off the side of Ben 10 scooter
Attacker(Joshua): what ya after doing you numpft