A person who exclusively listens to "independent" or "underground" music, and then proceeds to shut out any music style that does not adhere to their own strict principles. Often they will not associate with and indeed look down upon those who listen to anything remotely commercial
To spot an indie fascist, head to your nearest locally owned record store, pretentious coffee shop, or arthouse bar and look for someone wearing a scarf, thick-rimmed glasses, and possibly women's jeans and a beanie. A beard may also be present on some varieties (particularly the northwest indie fascist).
Don't bother arguing about music with them, your tastes are obviously inferior.
I thought Rob was going to tear my head off when I put that Godsmack
CD in, that guy's a straight up indie fascist!