Nimrod is described in Genesis as "the first on earth to be a mighty man" and "a mighty hunter before the Lord." It's easy to see how people made the leap from one mighty hunter in the Bible to calling any hunter a nimrod. A lesser-known fact is that nimrod has seen some use in English as a noun meaning "tyrant" (apparently, the mighty Nimrod was not reputed to be an especially benevolent king), although that sense is now essentially obsolete. The legendary Nimrod is also sometimes associated with the attempt to build the Tower of Babel. Because the tower resulted in the wrath of the Lord and proved a disastrous idea, nimrod is sometimes used with yet another meaning: "a stupid person."
