The word "most dead-tired" is used to describe a state of extreme exhaustion or weariness. Some antonyms, or opposites, of this phrase could include "energized," "refreshed," "revitalized," "alive," or "perky." These terms suggest a sense of vibrancy and vitality, which is in stark contrast to the dull and lifeless feeling associated with being most dead-tired. Other antonyms could include "wide-awake," "alert," "sharp," "focused," or "responsive," implying a sense of clarity and acuity that is lacking when one is most dead-tired. Whatever the antonym, it is clear that being most dead-tired is a far cry from feeling alive and energized.