If someone does something at the eleventh hour , they do it at the last possible moment.
He postponed his trip at the eleventh hour.
...last night’s eleventh hour agreement.
N-SING : usu at the N , N n
ELEVENTH HOUR
Meaning of ELEVENTH HOUR in English
Collins COBUILD Advanced Learner's English Dictionary. Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне. 2006