Usually followed by up: to dress up, to wear smart or special clothes.
To take a vacation in a dude ranch.
To address someone as dude.
An inexperienced cowboy.
A tourist.
A man, generally a younger man.
A term of address for someone, typically a man, particularly when cautioning them or offering advice.
A term of address, usually for a man, conveying awe, excitement, surprise, annoyance, etc.