freak

(noun) a person or animal that is markedly unusual or deformed. Synonyms: monster, monstrosity, lusus naturae.

(noun) someone who is so ardently devoted to something that it resembles an addiction. Synonyms: addict, nut, junkie, junky. Examples: "A golf addict." "A car nut." "A bodybuilding freak." "A news junkie."

(verb) lose one's nerve. Synonyms: freak out, gross out. Example: "When he saw the accident, he freaked out."