Derived from goose-feather or cuckoo feather (cuckoo bird), a feather, or a feath, is a crazy-person. He or she is usually out of their mind and in their own world, but not all the time. They tend to "feath" out or "flap" around wildly. When agitated, which occurs often, feathers can become ruffled. This is also detected through the possessed, wild-eyed look of the feather. A flapping sound can be used to reference the actions of said feather or the presence of a feather.
"That girl at the party was a total feather."
"Did you see that guy on the bus feathing out?"
"Dinner was great, until I got "feathed". I am not sitting next to Bob's sister again."
"Feath came over last night, and was flapping every which way and left feathers all over the ground!"