I felt foolish and a failure.

我自觉是个愚蠢的失败者。

《牛津词典》

That's a foolish action.

那是个愚蠢的行为。

youdao

An adult can sometimes act as foolish as a little child.

大人有时也会像小孩那样愚蠢行事。

youdao

That is,he makes a situation worse for himself by doing something foolish because he is angry.

VOA: special.2009.09.13

For joy, apparently, it was all Franny could do to hold the phone even with both hands. For a foolish half minute or so there was no other words, no further speech, then "I can't talk anymore, buddy."

为了欢愉，明显是弗兰尼拿着电话,或者用双手能做的，在大约半分钟里,没有其他的话了，也没有讲话了，然后说，我不能谈论任何人，巴蒂“

耶鲁公开课 - 1945年后的美国小说课程节选

He says these have been carried out in public, he has gone around in the market and in the open and in the public forum questioning, interrogating and obviously making a variety of people look foolish.

他说这些都是公开进行的，他游走在市集,在公开,及公共的论坛，提问，质问,且明显地让任何人难堪。

耶鲁公开课 - 政治哲学导论课程节选

Despite a foolish mistake in a report by the International Panel on Climate Change suggesting that this might happen quickly, no one believes that to be the case.

ECONOMIST: Pollution in the Himalayas

But taking open-plan offices to extremes by commissioning an 1, 800-foot-long oddity is a foolish attempt to revive a bygone idyll.

FORBES: Facebook Opts For A Mosh Pit; Reddit Builds An Idea Sanctuary

Putting a muzzle and straitjacket on her and then scripting her so tightly that she came across as foolish was a "colossal blunder, " according to one of Palin's closest aides.

CNN: Commentary: What Alaska learned about Palin