1. A monkey born of unknown origins that is fond of crack-like areas. Can lead to painful irritated red areas.

2. the result of larger than normal thighs rubbing angrily against each other
Man that rash monkey is really riding me.
Did you see the size of that rash monkey, she really should apply lotion.
by The Dubber May 28, 2008
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Someone who knowingly has sex with people after discovering that they have an STD, spreading it.
Is Rachel really going out with that guy? She knows he's a rash monkey, right?
by theccw November 11, 2019
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