Illfamed refers to something or someone that has a bad reputation. Its opposite, a word that denotes a good reputation, is well-known. Another antonym for illfamed is renowned, which means famous for something good or honorable. Honorable, respectable, and distinguished are other antonyms for illfamed that imply high regard or admiration. On the other hand, infamous is a synonym of illfamed and denotes a negative reputation. The opposite of infamous would be famous, well-regarded, or well-known for doing something positive. In summary, antonyms for illfamed are words that represent a good reputation, honor, and respectability.