Someone who commits acts of grime, not terrifyingly grimy, but quasi-grimy...such as stealing a drink that is left unattended at a bar. Or eating a roomates last slice of pizza they were saving for after thier part time shift at Barnes and Noble.
It is dervied from Grimaldo Used Auto Sales on Chicago's illustrious Archer Avenue.
Grimaldo himself is not a known grime, however he is the root behind the word. WHo would want to purchase a used car from someone named "Grime-aldo"
Jay just chugged that douche bag's beer he left unattended at the bar, what a grimealdo!
We walked in on west jerking off to some girl's myspace page, he is a straight grimealdo.