The antonyms for "ill-omened" are words like auspicious, fortunate, lucky, propitious, and serendipitous. These words imply positivity, good fortune, and a favorable outlook. An auspicious event is considered to be a sign of good things to come, whereas an ill-omened one indicates a potential for negative outcomes. Fortunate and lucky both denote good luck, while propitious implies a situation that is promising for achieving success. Serendipitous is an adjective used to describe an unexpected and fortunate discovery or occurrence. Using these antonyms for ill-omened, you can communicate a sense of optimism and positivity.