1. Someone who is overly-emotional, usually in a negative way
2. Chronically and outwardly depressed
Someone can be called emo if they have at least two of
the following qualities: always dress partially or fully in black (because it "reflects the color of their soul"); wear very tight and restricting clothes (constantly in contact with the skin, because they are usually deprived of any
physical contact with other people such as hugs); seem to talk mostly about how sad, unfair, or hopeless their life is; cut their own wrists; or attempt to express their emotions through
excessive amounts of boring dark art or poetry (also includes music).