1)A term for an employee or co-worker who is slower than most and often makes many mistakes even after considerable time on the job. The term Clem can be said to there face because they are often unaware what it means.
2)A term for a friend, roommate, hallmate, or general acquaintance that makes dumb decisions when sober and even dumber decisions when drunk and continues to make such dumb decisions because they black-out and forget what they have done the previous night.
"Wow Rickey is such a Clem
he went up to Emily's room last night and tried to open her door by rubbing his dick on her door knob."