1. A thing or occurrence that is markedly unusual or irregular: A freak of nature produced the midsummer snow.
2. An abnormally formed organism, especially a person or animal regarded as a curiosity or monstrosity.
3. A sudden capricious turn of mind; a whim: "The freaks of the psyche can no more be explained than the Devil" (Maurice Collis).
1. A drug user or addict: a speed freak.
2. An eccentric or nonconformist person, especially a member of a counterculture.
3. An enthusiast: rock music freaks.
adj. Highly unusual or irregular: a freak accident; a freak storm.
intr. & tr.v. freaked, freak·ing, freaks Slang
1. To experience or cause to experience frightening hallucinations or feelings of paranoia, especially as a result of taking a drug. Often used with out.
2. To behave or cause to behave irrationally and uncontrollably. Often used with out.
3. To become or cause to become greatly excited or upset. Often used with out.
---American Heritage Dictionary