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A person who will hump the shit out of someone's behind, usually until sore. Happens to either males or females.

Can also be used as a compliment, usually to someone who fucks a lot, or is really hot and gets girls.
That guy is such a rumpthumper, or Dude! She just got rumpthumped!
by rumpthumper March 10, 2011
An idiotic person, often a homosexual.
Valentine is such a rump-thumper!
by Matt October 27, 2003