In our culture the word "fuck" is one of the more offensive things one can say. It is often said when one is upset. People say "fuck this" when they've had enough and don't care anymore. "Fuck you" is a fairly strong insult. To "fuck up" means to make something go wrong or turn out badly. To "fuck" or "fuck over" means to cheat or hurt someone.
But the number one definition of "fuck" is to have sexual intercourse.
I just want to say — i think that's pretty fucked up.