It's the state of being when you do something very very well. Particularly at a sport, like in Soccer when you score a goal and you do a dance and scream, "I'm on FI-YAH!"
Come on dude, don't do the Fi-Yah! dance. You didn't even score a bloody goal...
by Jaques Pellegrino May 14, 2009
A slang term for "fire". Pronounced "fai-ah".
Damn, that bitch is on fiyah!!
by refuze May 28, 2005
A variation of the word fire. Fiyah is slang describing anything that is hot or dope (good). First used by a group that goes by The Fiyah Station in 2001.
Them boys be spittin straight fiyah on the mic!
by T davis April 29, 2008