A person who looks at their cell phone and pretends to be texting or that someone is calling them to give the illusion that they have friends.
"That guy is always on the phone, does he have a girlfriend now?"
"No he's a celloner. He's just talking to himself."
Justin Timberlake Syndrome.
When a person ditches all their friends to go off alone thinking they're the best and then quickly turns into a doushebag.
"I havn't seen Fred around lately, what's up?"
"Oh, he has J.T.S."
"Ah I see, what a doushebag."
"You guys are holding me back, I'm going to make my own team and fucking own you all"
"Whatever you say JT"