The meaning of " DUDE" = A Townsman, The meaning of "GUY " = A odd figure, or A fellow.

Dude means a stuck up person who dressed overly well or a man excessively concerned with his clothes, grooming, and manners. Guy is an informal term for a youth or man ,it has many kinds like good guy, bad guy, cool guy, big guy

I know the word "dude" from "dude ranch". This seems right: http://en.wikipedia.org/wiki/Dude