Random title usually used to describe someone with a shy disposition. If male, is usually homosexual and very timid. If female, is usually very timid, but very ferocious in bed. Warning! Do not overuse Z!
That guy's a real Z! He was going into that chick flick with 4 other guys!
Damn.. That girls a definite Z. She may be shy on the outside, but I bet she's a hell of a ride.