Fangirl

Noun: Someone who is obsessed with someone or something to an extreme degree. They are in a/many fandoms. Fandoms can include TV shows, books, movies, youtubers, and so much more. Usually, fangirls have a Tumblr, which is basically a meeting website for fandoms.
Verb: Having so many feelings that you cannot physically act normal at the moment.

Some people may use Fangirl in a way that may be incorrect. It is often annoying and ditzy.

Noun: omg David Tennant in Doctor Who. omg omg omg ily ily ily. SO MANY feels omg nope. GOTTA CHECK tumblr
Verb: I am fangirling so hard right now.

Ditzy

Real Fangirl: *Wears doctor who t-shirt*
Fake Fangirl: omg I love doctor who, that's the one with the car and they drive and fight demons and stuff. I am fangirling so hard right now.