An eccentric, ditsy, arcane, funny, person. Is generally a goodnatured and sympathetic person. Not to be confused with a "wackjob," who can be nasty,or violent.
Aunt Rosemary's fondness for multiple cats, Minnie Pearl hats, and alien abductions was never a source of shame for Fred, but rather a source of pride. He thought it surely must qualify her for the mythical "Wackadoodle Hall of Fame."