Inauspicious is an adjective that describes an event or situation that is not likely to be successful, favorable or prosperous. On the contrary, auspicious means an event or situation that is likely to result in success, prosperity, or happiness. Some antonyms to inauspicious include propitious, fortunate, opportune, successful, and promising. Other antonyms for inauspicious may include prosperous, fruitful, and favorable. In short, the antonyms of inauspicious, such as auspicious or propitious, describe situations, times, or events that are lucky, favorable, and likely to bring good fortune or success.