old head
n.— «Donnie excused himself. An emerald-green Oldsmobile driven by a man in his 20s pulled up to the corner. Donnie slinked into the back seat. “That’s his old head,” said one of the boys, using street slang for mentor. He was Donnie’s boss.…He introduced Mikey to the essence of being a man in their neighborhood—hustling while armed. “You can find an old head and he don’t care that much about you,” Mikey said. “He knew I had potential to stand on the block with a gun on my hip.”» —“Philly’s drug dealers: Younger all the time” by Simone Weichselbaum Philadelphia Daily News (Pennsylvania) Dec. 27, 2006. (source: Double-Tongued Dictionary)