1) short for 'most definately'
2) Hell yea; fo'sho'
3) the pun is on the rapper Mos Def, however his name is completely irrelevant to this insert
*an asian girl walks by with a big ass*
1)Would you hit that?
"Should we go to 7-11?"
(coming from "most definently")...meaning you strongly agree with someone else offer
Yo id rip that girl wide open...
Oh most def...most def
It plays off the term, "High Def."
Due 1: "Dude, we should get more beer."
Dude 2: "Most Def."