"Shit" can be used as an expression of surprise, anger, or pain. "Shit! I just slammed my finger in the car door!" It is also used as a more familiar way of saying stuff. "We went to the animal shelter today. They have dogs and shit." "Let's go to Walmart. They have all kinds of shit so I'm sure will find what we need." Something of a variation of the second meaning, it can also be used to mean "stuff that I like". "What kind of music do you like?" "I like Charles Mingus and Eric Dolphy." "Ah Mingus and Dolphy, now that's my shit." It can be used to mean poop/feces. "The animal shelter has lot's of dog shit." (NOUN) "My dog shits on the carpet if I don't take him outside." (VERB) As a variation of this meaning, it can mean "bad stuff. "Cheap toys from Walmart are always shit." Or as an adjective, just "bad". "Cheap toys from Walmart are always of real shitty quality." "Bullshit" means something that's false or not completely true. It often has the implication of either the bullshit or the person saying the bullshit is taking advantage of the stupidity of others: "Religious belief is such bullshit. No one intelligent believes in God these days." "New-age, self-help books are all bullshit. They pretend to be profound just to make millions of dollars off of dumb, suburban housewives." This can also be used as a verb: "I didn't wreck your car. Maybe it was one of your friends." "Don't bullshit me! I saw you take the car last night!"

You can say shit alone, like the other swear words: Shit! Fuck! Crap! Dammit! Goddammit! Shit and crap both mean poop, feces. You can also call something shit, or say it is shitty (it is crappy, it is useless or not well-made). ex. That little shit. or This computer is shitty. This computer is shit. When someone yells Bullshit! it means "I don't believe you!" or "You're telling lies!" ex. That's bullshit! I call bullshit! Quit your bullshitting! It can be abbreviated to BS. ex. That's BS. There is a card game called Bullshit, but of course if you don't want to say that, you can say "Let's play BS." You can also say someone is 'full of shit' = they are full of lies or other bad qualities, full of crap (useless). They are curse words and are very vulgar. But if all your friends talk like that, they will not find it offensive unless you use them offensively.

"Shit" - We normally use it an an expression but can also be used to mean Poop or Feces. "Bullshit" - It's normally used to express that you think what the person is saying is untrue or lies.

They are a little offensive. Do not say "shit" or "bullshit" in a job interview, or you will seem unprofessional. If you are with people who use these words, it is OK to use them.