When it comes to antonyms for "gruelingly", there are a myriad of words that come to mind. "Easily", "effortlessly", "simple" and "pleasantly" are just a few examples of words that may be used in place of "gruelingly". While "gruelingly" implies a difficult and arduous task, its antonyms suggest a much more manageable and enjoyable experience. If one desires to convey a sense of simplicity and ease, using one of these antonyms will surely do the trick. So, the next time you find yourself struggling to come up with an antonym for "gruelingly", remember that there are plenty of words that can convey the opposite meaning!