Mangy means foul, worn out, old and vile
Figuratively, the previous answer is absolutely correct. Literally, it describes an animal afflicted with mange mites which cause the animal to scratch...
Mange is a skin disorder, usually seen in dogs. The term has become a slang insult. Here are some sentences. "That mangy dog just stole my horse!" the cowboy yelled. Rover's mangy skin responded to...