Definition of: freak

(frēk) noun
1. A sudden causeless change of mind; a whim.
2. A malformation; monstrosity.
3. Slang One given to the use of drugs, especially illegal drugs.
4. Slang One who is very unconventional.
5. Slang One who is very enthusiastic about something: an opera freak.
—adjective Strange; abnormal.
—to freak out Slang
1. To experience, often unpleasantly, the effects of drugs, especially psychedelic drugs.
2. To behave as though one were under the influence of a psychedelic drug. [Origin unknown]
—freak′y adjective