Someone who thinks they know everything but knows nothing.A polite way of calling someone a smartass around proper people or company.
Johnny, you are such a smart one. Or ....Nice going smart one.
by swissmocha April 01, 2005
smart one is just a sarcastic way of saying someone is a dumn nut.
"most of my friends are smart ones"...or "man u r such a smart one"
by glonkabletotla June 09, 2009