bullshit

A bull's semen is used to breed cattle, and that's basically where the word "bullshit" comes from.

The word "bullshit" has taken on a few different meanings over time. One common way it's used is as an expression of frustration or disappointment when something doesn't make sense or isn't what you expected. For example, if you're told there'll be no lines at the airport and then you end up waiting in a huge line, someone might say "this is just bull!" They don't mean anything to do with actual bulls.

Another way people use this word is as a more forceful version of saying something's untrue or false. It can be used like that in an argument when you're sure the other person is being dishonest. Some people are careful not to use "bullshit" like this because it sounds stronger than they intend, but it's often used as a way of emphasizing how strongly someone feels about what's being said.

It's worth noting that if you hear someone say something's "bull", without the word "shit", they're probably just using "bull" to mean nonsense or foolishness.