Bullshit

Bullshit (also selmo, bullplop,  bullbutter, bovine stool, simply B.S.) is a common English language 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."). 

References

Category:English profanity