The word "unattiring" refers to a state of not being tiring or exhausting. Antonyms for this word would include "tiring," "exhausting," "draining," or "fatiguing." Other antonyms, which describe a state of activity, would include "invigorating," "energizing," "stimulating," or "revitalizing." On the other hand, adjectives like "boring," "tedious," "monotonous," or "dull" could be antonyms for "unattiring" when used in the context of a task or activity. Depending on the intended usage of the word, there can be several appropriate antonyms to describe the opposite of unattiring.