Antonyms for the phrase "most long-delayed" include "immediate," "instant," "prompt," "swift," "timely," and "expeditious." These words describe actions that are done quickly and efficiently, without any delay or hesitation. "Immediate" refers to something that happens without any delay, while "instant" means happening instantly without any delay or reaction time. "Prompt" describes something that is done with urgency or without any delay, while "swift" means happening quickly or without any delay. In contrast to "most long-delayed," these words suggest prompt, efficient, and timely actions that are performed without any delay or hesitation.