1. a bear which forsakes its natural food source for foraging in dumpsters.
2. a sparing person who prefers to eat food which is no longer fresh or is past its expirion date, rather than discarding it.
"Why did you throw away my lunch leftovers?"
"Because they were in the fridge for three weeks now!"
"But they were still edible!"
"I wound't marry you if I knew you are such a dumpster bear."