If you describe behaviour as foolhardy, you disapprove of it because it is extremely risky.
例句
When he tested an early vaccine on himself, some described the act as foolhardy...当他在自己身上试验还处在初级阶段的疫苗时,有些人说他的行为是蛮干。It was foolhardy to have refused.拒绝是极不明智的。
英汉词典释义
adj.
<贬>莽撞的;有勇无谋的
He paid for the foolhardy act with his life.他为鲁莽的举动付出了生命的代价。
英英词典释义
Adjective
1. marked by unthinking boldness; with defiant disregard for danger or consequences;
"foolhardy enough to try to seize the gun from the hijacker""became the fiercest and most reckless of partisans"-Macaulay"a reckless driver""a rash attempt to climb the World Trade Center"