a grunger at least on the surface is somebody who minds their own business smokes their own weed
/hash and is fairly happy until cries of greebo
or 'grunger boi' by the local burberry-wearing faschists upset everything. this however does not define grunge, (nor indeed does kurt cobain) these chavs
are 'but fleas annoying a glorious tiger'.
(also anyone who wishes to rush to the defense of these people, remember two things 1: THEY started the labelling of people based upon appearance or preferred music and 2: they will thank you for defending them buy spitting in your face and robbing you).
while the word grunger did originate from the US grunge music scene (Nirvana, Smashing Pumpkins, Foo Fighters etc.) the 'subculture' HAS moved on, many grungers could be described as a scruffy golden-virginia-smoking mixture of many other alternitive
Many grungers do scare pensioners with their visual offensiveness but this is usually purely unintentional (also said pensioners should be more scared of the group of sportswear coated yobs waiting around every corner for someone to mug so they can get a 'MaccyDeees bruv innit').
As a grunger myself i am the first to admit we care little for appearances, especially our own, but this may not be in the way you think. first of all clothes are probably bottom of a typical grunger's shopping list, also a strong anti-capitalist streak steers grungers away from the brand name crap with ugly logos slapped on the front (or anywhere really). This leads to a sort of dark hippie
/metalhead look; long (not necessarily greasy) hair, torn baggy jeans, often tattered metal band t-shirts, beanie hats, khaki and really worn skate shoes.
Finally as we reach the end of this loooooooong definition i must point out that grungers can skate, listen to whatever music they want and don't have to be in a band or even play an instrument because THAT is what grunge is about freedom from opression inflicted upon society by brain dead nazi-fucks. We don't even really need to define grunge (even though i have spent half an hour doing just that), 'grunge' is what the individual grunger wants it to be.
and in the words of violent J; fuck you if you don't like it rude boy