expression, godan verb (-su)
miss a big chance; let a golden opportunity slip by
Idiomatic expression meaning to fail to seize a major opportunity. The image is of letting a long snake escape. Can also refer to allowing an enemy to get away. Often used with する as 長蛇を逸する.
彼は優勝のチャンスを長蛇を逸した。
He missed a golden opportunity to win the championship.
敵将を取り逃がし、まさに
They let the enemy commander slip away, truly a case of letting the big one get away.