Does NOT have to be unknown, it can also be a rapper that was underground yet kept the style and became extremely popular and well-selling commercial material
Pharoahe Monch and Wu-tang clan have music that is not bombarded with commercial material yet sell heaps
by Big Mac December 26, 2003
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a zit that is deep, with no white head, painful, and bulbous, it takes a long time to head up and is generally super annoying.
dude, i got a huge undergrounder on my forehead!
by prot1a5 September 21, 2005
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those fucking annoying pimples that are like a solid mound protruding from your head, hurt like hell, yet don't have a head so you can't deal with them
you: fml this new pimple is giving me a headache
friend: ouch, an underground?
by Catriine September 9, 2010
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A twenty-first century marketing buzz word used to convince teens that the over-hyped, over-produced, corporate-friendly crap they listen to on the radio station everday is actually "unique, hip, different" or that they somehow aren't part of a target market in which they all obediently buy the same crap.
Yeah, that hot new underground rapper made his debut on TRL today.
by samhain November 19, 2004
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Also called the UG. A message board forum for MMA (Mixed Martial Arts) fans and fighters. Members often refer to themselves as UG'ers. Contains many UFC and PrideFC elitists/nuthuggers that hate TUF noobs(new fans due to The Ultimate Fighter Reality show). Members tend to belittle others for liking certian fighters, or for not knowing who certain figters are.
There are different levels of access to the forum, a free or MUDNAMER account and a Pro account(blue, green, red name)which costs $$.
Mudmaners usually get shit on by the Pro UG'ers for not buying a name (forum namism if ya ask me).

Ban this mudnamer, The UnderGround doesnt need anymore TUF noobs.
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Someone who is similar to or even better than the top dogs and has the power to be influential, yet is very underrated.
All the way up until he became mainstream with his "?" album, XXXTENTACION was an Underground King.
by FredTheFriendlyFarmer September 24, 2019
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rap that is created by an artist who does not have a recording contract.
I was listening to some hardcore underground rap last night.
by swagasauruse December 10, 2011
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