An extremely informal word used for a variety of purposes.
Can be used to describe love, express hate, show shock or just make a sentence seem way more fucking exagerated and fucking agressive than it need to fucking be.
person 1: "dude what the fuck was that?"
person 2: "I don't know man, the toaster just fucking exploded lol"
Fuck as many meanings.
1) Can be used when forgetting something 2) Can be used when saying sex 3) When cursing out someone
4) When surprised or asking a question
Example 1 - Fuck! I forgot my book at home!
Example 2 - I'm gonna fuck Lana tonight!
Example 3 - Fuck you Brian!
Example 4 - What the actual fuck is going on here?!