The deep southern drawl contraction of "you all are".
1. "Hey! We ain't no freakin' queers! Yaller gay!"
by Sean Geranium March 14, 2007
a person, usually a redneck southerner or a white guy trying to act like a rapper; who always says "y'all". Often, they tend to say it twice in the same sentence.
Man, that redneck over there is such a y'aller
by The Kentucky Yankee August 01, 2004