Whenever he thought about it, he felt terrible. And so, at last, he came to a fateful decision. He decided not to think about it. ~John-Roger and Peter McWilliams
Q:

Dear 100 Hour Board,

So I was reading in Genesis tonight (chapter 10) and it mentions how Nimrod was a great man in the sight of God (or something like unto that). My question, then, is how did calling someone "Nimrod" come to be an insult?

- Trissy

A: Dear Trissy,

Genesis 10:8-9 says that Nimrod was "a mighty one in the earth," and "a mighty hunter before the Lord." I had only ever heard someone called a Nimrod if they were a fantastic hunter. The Oxford English Dictionary adds that it's frequently used in an ironic sense—you might call someone who wasn't a great hunter a Nimrod to mock them.

They also have a definition that matches your question: "N. Amer. slang. A stupid or contemptible person; an idiot." Since this is slang, I decided to try the Urban Dictionary and see what they said. The top explanation referred to Dictionary.com, so I went there. They cite the American Heritage Dictionary, which explains: "[P]robably from the phrase 'poor little Nimrod,' used by the cartoon character Bugs Bunny to mock the hapless hunter Elmer Fudd."

As the Urban Dictionary writer points out, the reference would be a bit beyond most small children, who would only grasp that it was being used insultingly (in an ironic sense, since Elmer Fudd is clearly no Nimrod). From there, it apparently got picked up and turned into the slang you know.

Sounds plausible, though I'm not sure how you'd verify it. Apparently the American Heritage Dictionary is satisfied, though.

—Laser Jock