Slow of mind, lacking interest or point. Lacking common knowledge. Possibly a victim of brain damage.

See STUPID,MORON,IDIOT,OBTUSE
"YO SHANEQUIA, Isn't that girl so mo0sy!?"
by Jadyyn Gangrape March 21, 2005
Get the mo0sy mug.
Comes from the latin words moooretarded, and syyyisdumb, which means to be dumb. see stupid.
psh, Becky, don't pull a mo0sy, now.
by le raerae. March 22, 2005
Get the mo0sy mug.
One or something that seems brilliant, in style, and considered vogue to peers
WOAH! That's SO mo0sy!!!
by Farrah March 22, 2005
Get the mo0sy mug.