..Wha?
It means you're either confused or dont give a flying fuck.
Best used when someone says something retarded.
(remember its lowercase w! uppercase W means something different!)
Jack: "If you times something by 0 it means that it's the same because 0 is nothing."
Everyone: "w"
With & Win
Me and my football team took a W last night
I went w him and his friends to hangout