Another name for a pontiac grand am car. Given because the grand am is hood, gangsta, pimp, and just plain hot sauce.
"Playa, you see that gamallac rollin on 20's? That shit was tiiiiiight."
A gamallac is a term used for the great vehicle known as the Pontiac Grand Am.
Son, I don't think you want to line your car up against a gamallac.