Where did cap slang originated?

The term “to cap” has been part of Black slang since about the late 1930s, according to Green’s Dictionary of Slang. However, the term typically has to do with bullets or shots. But, this is only one usage of the term cap. It also meant “to surpass,” coming from using cap as the top limit of something.

What does cap mean in slang?

The expression “cap” is slang meaning “lie” or “bullsh! t” The expression “no cap” is slang meaning “no lie” or “for real,” The expression “capper” is slang meaning “liar” or “faker” The expression “capping” or “cappin’” is slang meaning “lying” or “faking”