noun. a grunge onion. someone who is so filthy they exude grease. a person who always looks sweaty and out of breath. also, a butter grungion is like a sweatier grungion.
1. "dood, why don't you buy some shampoo, wash your forehead, and stop being such a butter grungion?"
2. "oh man, i feel like such a grungion, i gotta wash up or a copy of superunknown is about to fall out from uner my arms."