To defecate.
To excrete (something) through the anus.
To fool or try to fool someone; to be deceitful.
Twelve hundred dollars!? Are you shitting me!?
To annoy.
That ad shits me to tears.
The act of defecating
Faeces
An intensifier, often applying more to the whole utterance than to the specific word it grammatically modifies; same as fucking.