Real Dictionary

freak out
to be or cause to be in a heightened emotional state, such as that of fear, anger, or excitement
to enter into or cause a period of irrational behavior or emotional instability, as under the influence of a drug
to experience, esp. in an extreme way, the mental reactions, hallucinations, etc. induced by a psychedelic drug
noun: an act or instance of freaking out
noun: an episode of bizarre experience or behaviour
phrasal verb: If someone freaks out, or if something freaks them out, they suddenly feel extremely surprised, upset, angry, or confused.