foolhardy

在暴风雨中独自出海真是太鲁莽了。

It was ___foolhardy to sail alone during the storm.

不查看天气预报就去登山，实在太过鲁莽。

It was ___foolhardy to attempt the mountain ascent without checking the weather forecast.

把全部养老金投进一家科技创业公司，是鲁莽乐观之举。

Investing his entire pension in a single tech startup was an act of ___foolhardy optimism.