An adult, most commonly a male, who has never fully developed or matured emotionally and is characterized by a low degree of self awareness, awkward
interactions with other people, a lack of empathy
and an inability to achieve intimacy
Gary: "Ken, I hate to be the one to tell you this but Uncle Gilbert has cancer."
Ken: "More cottage cheese and peaches."
Gary: "Excuse me?"
Ken: "More cottage cheese and peaches. Bring me some."
Gary: "Ken, dude, you are emotionally stunted."