A person who is obviously weird, strange, and does retard-like things, but is a fully functionalhuman being, or whatever species they are. Usually they are assholes, but they're usually enjoyable and funny.
They're claiming that her new book goes under the Romance genre, but it's really just plain, simple Fucktion. There's no emotionalconnection between the protagonist and her partner.
A person that can have many drinks, become drunk, and still function perfectly normal. It's hard to tell whether or not this person is drunk unless you ask them to recite something.
Girl: I was so drunk last night but I had a normal texting conversation with my boyfriend.
Other girl: That's weird but you might be a functional drunk.