Definitions by Watchful

have one 

This is a shorthand for the overused expression, "Have a good day," and is slowly catching on to be much more hip!

As I drop my friend off and he leaves the car, I shout "Have one!"

He replies, "Word...later!"

have one by Watchful December 24, 2008

have one 

short for "have a good one," which itself is, of course, short for "have a good day."

Johnny: "See you tomorrow Bill"

Bill "Have one!"

have one by Watchful October 30, 2008