一ひと役やく買かう

expression, godan verb (-u)

take on a role; play a part; lend a hand

Used when someone voluntarily takes on a role or contributes to a group effort, often in a helpful or proactive way.

• 彼かれはプロジェクトの成せい功こうに一ひと役やく買かった。

  He played a part in the project's success.

• 地ち域いきの清せい掃そう活かつ動どうに一ひと役やく買かうつもりだ。

  I intend to lend a hand with the local cleanup activity.