A person who is unable to eat without spilling. Someone who spills something sticky or of a jam-like consistency on themselves. Someone who covers themself in jam or marmalade before canoe trip. Someone with food on they're face and they don't realize its there. Someone who spills messy food on themselves.
Bill:that was the best sloppy joe i've ever had!
Jen:great, now go and change your shirt you fuckin' jam eater!