An unreliable person. Someone who shows up late, doesn't pay rent or repay loans, can't hold down a job for very long, etc. Your typical moop has tattoos, piercings, court-ordered child support, a substance abuse problem and a petty criminal record. One step up from a rubadub.
I thought tending bar would be a fun job, but I couldn't stand listening to the moops tell their stupid fishing stories all day!