Top Definition
A phrase used to describe a person who should not be underestimated. A practical term which can be used with most anyone in any situation where the individuals abilities, conduct or intelligence might be underestimated.
I know the Kobe and the Lakers have won nine games in a row, but Manu Ginobili is a Laker killer. Don't sleep on Manu Ginobili!
by Tom_in_SA March 01, 2009

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