A person with borderline personality disorder, usually hailing from Liverpool, UK and relies on the personalities of fictional characters to identify themselves with because they are too insecure about themselves to be themselves. Also tend to be manipulative and gaslighters that are really just deep down sad and lonely and should seek therapy.
A way to catch yourself when about to say that dreaded s-word in front of children.
Guy washing his car in front of his son: "Shhhh-mookles I found another dent!"
Son: "What does shmookles mean?"
Guy washing his car in front of his son: "Look it up on Urban Dictionary, Sport."