To waste one's efforts; to labor fruitlessly so that one's efforts produce no useful result.
彼は何度も手紙を送ったが、結果が出ず無駄骨を折った。
He sent letters many times but got no result and thus wasted his efforts.
新しい計画は上司に却下され、チームは無駄骨を折った形になった。
The new plan was rejected by the boss, and the team ended up wasting its efforts.
無駄骨を折らないように、事前に条件を確認しよう。
To avoid wasting effort, let's confirm the conditions beforehand.