Isf

Internally sexually frustrated

Lack of sexual activity resulting in one feeling sexually needy.

My sex life has been dead, I’m so isf.

ISF

Insomniac Shitposting Freethinker, a community of "immature atheists" and "wannabe freethinker" to start a religious flame war

ISF is a place for you to make a racist joke towards religious people

Isfs

shorter for I speak fluent sarcasm

-duh! it was sarcasm!
-don't worry, i know, isfs

Isfs

Im so fucking stupid

Me:Whats 100x2?

Friend: Are you Serious?
Me: Wait nevermind isfs