noun

• (dated outside certain expressions) Someone or something that is markedly unusual or unpredictable.
  "The two-headed calf was a freak."
• (slang, chiefly derogatory) A person who is extremely abnormal in appearance, social behavior, sexual orientation, gender identity, or business practices; an oddball, a unique person, originally in a displeasing or alienating way.
  "Gentrification often starts with the artists, revolutionaries, freaks, transfolks, and queers (what I would call my people) moving into poor neighborhoods inhabited by people of color."
• (bodybuilding) A person whose physique has grown far beyond the normal limits of muscular development; often a bodybuilder weighing more than 260 pounds (120 kg).
• (informal, sometimes endearing) A very sexually perverse individual.
  "She's a freak in the sheets!"

verb

• (intransitive, slang) To react extremely or irrationally, usually under distress or discomposure.
  "When the owner found a bunch of beatniks in there, he freaked, but that was later."
• (slang, ambitransitive) To be placed or place someone under the influence of a psychedelic drug, (especially) to experience reality withdrawal, or hallucinations (nightmarish), to behave irrational or unconventional due to drug use.
• (transitive, dated) To streak; to variegate
  "Freakt with many a mingled hue."

noun

• (UK dialectal, Scotland) A fellow; a petulant young man.