Bullshit (also bullcrap, bullplop, bullbutter, bovine stool) is a common American English expletive. It can be used also as an interjection or as many other parts of speech. Usually, it is a noun, verb or interjection that describes a lie. It shows that someone is trying to deceive, e.g. "Stop bullshitting me" ("Don't try to deceive me. I know what you are saying is a lie.").