Dutch courage可不是“荷兰人的勇气”而是“酒后壮胆 ；酒后之勇；一时虚勇” 。

【例句】
He needed some Dutch courage before facing his boss about the pay increase.
他需要喝点酒壮壮胆，才能当老板的面谈加薪的事。

The poor man beat his boss by means of Dutch courage.
那个可怜的人借酒劲打了他的老板。