1) When pants are worn so low that it makes the wearer look like they have a full diaper on.

2) A really old person's pants. They are so old that they could be a fossil.
Person 1: Look Tyana at Adam's new fossil pants

Person 2: you could make natural gas outta those fossil pants!
by Kn0w1ng June 5, 2013
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When a male is horny all the time even after boning a chick

You can also take Viagra to become fossil pants so you are always good to go
Bro you are totally fossil pants
why do you say that
you just fucked 13 girls and still up
by Fossil Pants March 22, 2012
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