The mine was a dud.

这颗雷是颗哑雷。

《柯林斯英汉双解大词典》

The original metaphor practice was a dud.

最初的比喻(metaphor)实践失败了。

youdao

But Jobs likely knew he had a dud on his hands; consumers, for their part, hated it.

乔布斯心里很清楚，他手里拿的是个哑弹，一个失败的产品，消费者肯定会憎恨这个东西。

youdao

For stock pickers in particular, this may not be a dud market after all.

FORBES: Is It Time To Overweight Europe?

As a heist movie, however, this is a dud, the plot splintering badly in the middle.

NEWYORKER: The Good Thief

But at first Spirit's landing site at Gusev Crater was a bit of a dud.

NPR: Mars Rover Marks Second Anniversary of Landing