不遗余力不遗余力[bù yí yú lì]1.■spare no effort [efforts; pains]; be all out; be unsparing in one's efforts; do one's level best; do one's utmost to ...; go to all lengths; leave no stones unturned; make an all-out effort (to ...); make every endeavor; make the best of one's way; with all one's might; without sparing any effort