空むなしく

adverb

in vain; fruitlessly; to no purpose

Describes an action or effort that ends without the desired result, often with a sense of emptiness or futility.

• 彼かれの努ど力りょくは空むなしく終おわった。

  His efforts ended in vain.

• 一いち日にち中じゅう待まったが、空むなしく時じ間かんだけが過すぎた。

  I waited all day, but the time just passed fruitlessly.