A person who listens to grunge music (e.g. Nirvana) and dresses in the style that such bads adhere to (e.g. baggy, usually untidy looking, clothes). Others could be perceived to be grungers due to dressing in that style of clothing although they may not listen to grunge. To be a "true" grunger the person must do both.
Grunger= Music and clothing style match
Perceived grunger= clothing style only
Closet grunger= music only