As a noun it refers to dung. Therefore you could call a dung beetle a shit beetle.
It can also can be used in place of the mass noun, stuff.
"Get your stuff out of my house."
"Get your shit out of my house."
As a verb it refers to the act of eliminating waste.
"I pooped my pants!" My grandfather yelled.
"I shit my pants!" My grandfather yelled.
The past tense of the verb shit, is shat. He shat in his pants. He can also shit bricks, but this means that he is either surprised or going to be surprised, not that he ate the bricks and pooped them out. Though, if you've ever watched that TV show My Strange Addiction, shitting bricks does hold the potential to be an accurate description of what somebody did.
Deep shit can mean you're in trouble or you have a lot of cows. If you have a lot of cows and don't clean up after them, then you will litterally be in deep shit. If these cows happen to be bulls, then you can literally be in deep bullshit. Generally speaking, bullshit means to you're lying.
Shit can also hit a fan, though this usually does not mean someone must threw the shit at a fan. It's used to indicate a point in time where trouble comes to a head. My question is, do you know what happens when shit actually hit's a fan? I've personally never tried it, but I guess the answer depends on whether the manure in question is solid or mushy.
Did you know that poop is mankind's second favorite topic of discussion?
This post about shit is the shit. That means this post is great.
Agree or disagree?
(Also, for all you authors out there, how does the use of shit change your perception of the speaker in my example dialogues?)