This word is used to describe children who "Just Aint Right"
Synonyms: POPP, stupid, dumb, naughty, never going to fit in types, not mainstream, messed up, etc, etc, and so forth.
they have little or no potential to be normal until they get the right treatment/therapy.
Hose: No he doesnt, Johnny is a JAR!
Alex: This boy needs to go to the institution
John: Yeah, there is nothing we can do about it. He is a JAR.
Person B: "No, it's not SARS. It is JARS"
Person A: "Oh, that's good."
Person B: "No. Actually, it is terrible."