be at the mercy of

頻度
難易度
phrase
C2

to be unable to control what happens to you; to be in a situation where you rely on others or external factors

When the storm hit, the residents found themselves at the mercy of the floodwaters.

嵐が襲ったとき、住民たちは洪水の犠牲になった。

translation

phr. 〜の思いのままに