Antonyms for the expression "most eleventh-hour" can be described as timely, punctual, early, prompt, or premature. When something is done on time or ahead of schedule, it cannot be considered eleventh-hour. Timely implies that something happens at the right moment, precisely when it is needed. Punctual refers to things that happen at the exact agreed-upon time, without delay, or lateness. Early denotes that something is done before the expected time or before it is necessary. Prompt implies that something is done without delay or hesitation, while premature suggests that something is done too early or ahead of time, which may be unfavorable.