A person or animal that is markedly unusual or deformed. The circus featured a sideshow with a two-headed freak.
A person who is obsessed with or unusually enthusiastic about a particular activity, interest, or subject. He's a fitness freak who spends hours at the gym every day.
An unexpected and unusual event or occurrence. The storm was a freak of nature, causing damage that no one anticipated.
(slang) A devotee or habitual user of a specified recreational drug. Back in the seventies, he was an acid freak.