Being of Asian descent, I know what it means.
The term originated in the Korean War. In Korean dialect, a white person is called a MeeGook and a Korean person refers to himself as a Hangook. If you look on Korean-made cars you'll see that they have Hangook (they spell it Hankook) tires which means "Korean".
During the war, Americans shortened the name to just Gook. It was easier to say than Hangook so it stuck. During the Vietnam War, they adopted the term to mean any Asian person. They called the enemy gooks because of what their fathers had taught them about the Korean War.
I think it became a derogatory comment after Hollywood abused the term in any one of their 1000 Vietnam War movies. Ever since then, the slang term for Asians became gooks.
So now you know, and knowing is half the battle! GOOOO JOE!!!
