A person, typically a male, who is obsessed with going to the gym or working out. This person will spend hours upon hours bulking up, pausing only for protein shakes or supplement use. Gymheads often go after their own breed and tend to spend most of their time with those who love the workout grind as much as they do.
"Have you seen that guy at the gym?"
"Yeah, he's always there; that's where he spends all his time. He's a total gymhead."