What's a Mook?

This is my absolute, hands down, favorite insult. Especially since nobody seems to know what it really means. Problem is, neither do I. Any ideas?

Go watch Scorsese’s “Mean Streets”, see if anyone in that movie ever finds out what the answer is.

I’m sure this is completely irrelevant, but “mook” is a fairly well-known term in Japanese. Its an invented word that is a contraction of “magazine” and “book.”

I’ve heard it in referance to a morrocan low life or thug. Check french slangs and terminology. This is just a WAG.

From my dictionary of Trinidad & Tobago phrases:

“Mook: A very stupid person. See MING_PILLING, CHUPIDEE”

There you have it. Now I have no idea if that’s the same phrase as in Mean Streets, but seeing how Trinidadians have a fairly strong presence in New York, I could see how the term could spread to Italians and other groups there.

Hey there. My friend uses this one a lot. He apparently did some digging and he’s told me that it’s a derrogative term for people from South America (though I am not sure if he means a particular country or the whole continent). Though he uses it in pretty much any context. I don’t know if his explanation is totally accurate because I know that a Mook Jong or Mook Yan Yong is a martial arts wooden training dummy. This therefore makes the insult very fitting. Here’s a page that sells them and discusses their use:
Mook Jong Trainer
I’ve actually seen Bruce Lee, Jackie Chan, and other martial arts movie stars use these before but never caught the name. Later all.