The antonyms for the word "un-rewarding" are numerous and encompass a broad spectrum of positive attributes. Some of the most common antonyms include fulfilling, satisfying, gratifying, enriching, and enjoyable. These words describe experiences that provide a sense of accomplishment or pleasure, as opposed to something that feels like a waste of time or effort. Other antonyms for un-rewarding are lucrative, productive, beneficial and advantageous, which suggest that the activity yields some tangible benefit or advantage. By using these antonyms to describe activities, we can communicate the degree to which something is likely to be enjoyable, fulfilling, and productive.