dc;fo

Also see: DCFO, DCFY
Frequently used in the City of London trading floors as an equally abusive retort to those who band around the very rude "tl;dr".
Can also be used in combination with other insults, e.g.:
"dc;fo;ff" - don't care, fuck off fuck face.

Rude, usually unknown poster, in response to your helpful comment: "tl;dr"
You: "dc;fo"