n. & v.
n. 1 (also freak of nature) a monstrosity; an abnormally developed individual or thing. 2 (often attrib.) an abnormal, irregular, or bizarre occurrence (a freak storm). 3 colloq. a an unconventional person. b a person with a specified enthusiasm or interest (health freak). c a person who undergoes hallucinations; a drug addict (see sense 2 of v.). 4 a a caprice or vagary. b capriciousness.
v. (often foll. by out) colloq. 1 intr. & tr. become or make very angry. 2 intr. & tr. undergo or cause to undergo hallucinations or a strong emotional experience, esp. from use of narcotics. 3 intr. adopt a wildly unconventional lifestyle. freak-out colloq. an act of freaking out; a hallucinatory or strong emotional experience.
[ 16th c.: prob. f. dial. ]