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Someone who likes to plow guys in the ass.
Graham was accused of being a rumphumper when he was caught ass plowing his boss Tad.
by Nikolai88 January 12, 2008
A homosexual, someone who humps ones rump.
I always knew he was a rump humper.
by yesh,, March 18, 2008
Someone who humps someones ass.
Alex is an offical rumphumper, after she humped hevyns rump in the locker room.
by Alex January 19, 2003