2.: A rapper.
3.: Deaf - this useage is the least common, mostly by people who didn't understand it in the first place or mispronounced.
2.: "Mos Def is one of the best rappers of our time."
3.: "After that concert, they're mos def."
Mos Def in the music and film industry is the pseudonym of Dante Smith(2). Quasi legendary emcee who's soulfoul approach to hip hop and unique style has made him one of hip hops heavy hitters. He and Talib Kweli are known to collaborate alot, even making Black Star. Mos Def is also a pretty good actor who appeared in the remake of "The Italian Job" and the still in production "The Hitchikers Guide to the Galaxy".
Last a probably least, Mos Def is a brand of urban clothing(3). Most of they're stuff is pretty basic, but pretty cool. Hell, I'd pay for a sweatshirt that says "Mos Def"
Last and probably least,
Crack Whore:"Mos def!"
2-Man Mos Def is ill, but he was really pushing his luck with his newest album.
3-Guy 1:Hey look, is that a "Mos Def" brand sweatshirt?
Guy 2: *Looking at sweatshirt clearly labeled "MOS DEF"* man, you're lucky I dont have my trusty 2 by four to beat yo ass.