A number of sites on the internet including Wikipedia credit American troops still in basic training in 1940 before the US joined in World War II, and even point to one particular guy.

包括Wikipedia在内的不少网站都把这个词的来源归在美国士兵头上，那还是在1940年美国参加二战之前， 资料甚至指出了具体的某一个士兵。

youdao

Yank: (boldly) Sure, I 'II come out wet it. I 'ii show your I'm one of DE gang. Dere date millionaire guy, Douglas.

扬克：(无畏地)当然，我想出来了。我要让你们看看我也是这帮里的。那个家伙，百万富翁，叫道格拉斯的。

youdao

My favourite guy, Frederick II of Hohenstaufen, was in this period, and was remarkably modern in a way that, say, Charlemagne was not.

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Years ago there was a guy who on the surface was a World War II militaria collector but he was a BNP member with a wife in the police service.

BBC: Is it OK to collect Nazi memorabilia?