An item that is used as a weapon but wasn't originaly inteded to be a weapon. A homemade prison blade is a perfect example.
Dude! You just got shanked with a rake!
Dude look out! That broken beer bottle can be used as a shank!
A word that describes someone or anyone or anything that is interesting and well liked. Cool is over used and often to general and used for things that are often only a fad. The things and people that are in actual fact cool don't care about being cool.
OMG! That dress would look so cool on you!
Dude that deck is freaken cool!