“TNUC” is code for a person who acts
like a real “
CUNT”. Its inception came about because you cannot say “
CUNT” in the workplace. It is spelled “TNUC” but when spoken you say “NUCK”, as the “T” is silent the "K" is hard.
Its popularity arose because the sound of the hard “K” is so satisfying, sort of like saying the word “FUCK”.
Sometimes such coarse language is simply warranted.