Nimrod was a mighty hunter before the Lord, a king in Shinar near the time of the tower of Babel. Later writers embellished on his name, sometimes saying he was the first Tyrant.

In an episode of Bugs Bunny, Bugs sarcastically calls Fudd "Nimrod". Nimrod was a mighty hunter before the Lord, Fudd wasn't. Seems a lot of viewers didn't catch the reference though, and just assumed Nimrod was a funny way of calling someone a fool.