徒あだ

na-adjective, noun

vain; futile; transient; frivolous

Describes efforts, hopes, or things that end up being empty, pointless, or fleeting. Often used in literary or reflective contexts.

• 彼かれの努ど力りょくは徒あだになった。

  His efforts came to nothing.

• 人じん生せいは徒あだなものだと思おもうこともある。

  Sometimes I think life is a fleeting thing.