The word "most reviving" refers to something that refreshes, renews, or invigorates. Its antonyms, on the other hand, mean the opposite - something that makes one feel exhausted, drained, or depleted.
One antonym for "most reviving" is "wearying," which means causing one to become tired or fatigued. Another antonym is "draining," which implies something that empties or reduces energy. "Exhausting" is another antonym, referring to something that requires a great deal of effort or leaves one feeling completely depleted.
Other related antonyms include "deadening," "lifeless," and "stagnant," which indicate a lack of vitality or energy.