As used, it's the noun, not the verb.verb
- 1.
INFORMAL
behave or cause to behave in a wild and irrational way, typically because of the effects of extreme emotion, mental illness, or drugs.
"I could have freaked out and started smashing the place up"
freak
/frēk/
noun
a person, animal, or plant with an unusual physical abnormality. someone who puts pineapple on pizza.