Function: noun
Date: circa 1821
1 : a venomous semiaquatic pit viper ( Agkistrodon piscivorus ) chiefly of the southeastern U.S. that is closely related to the copperhead ― called also cottonmouth cottonmouth moccasin
2 : a harmless American colubrid water snake (genus Nerodia ) resembling the true water moccasin
water moccasin