To spit hot flame. To make a lyrical line so hard that all of your bros legit can't help themselves but drool and start seizing. The ultimate bar. Something that comes out but never leaves the room. The word "one ear out the other" doesn't exist. It'll change your life.
"Da man dem spit big man cyphe, he be da big man boss man"
"Bro, he legit just cyphed so hard. That shit was too good, we need to find a beat for that."
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).