expression, i-adjective
spare no effort; work tirelessly; give one's all
A set phrase meaning to work without holding back, sparing no effort or energy. Often used to describe someone who works diligently and selflessly.
See also: 骨身を惜しまず
彼は骨身を惜しまないで働いた。
He worked tirelessly, sparing no effort.
骨身を惜しまない努力が成功につながった。
His unsparing effort led to success.