The definition of momentous is an important moment or something important.
An example of momentous as an adjective is a momentous wedding, an important event in someones life.
Of utmost importance; of outstanding significance or consequence: a momentous occasion; a momentous decision.
- I waited until evening to make my momentous call to Agent Brennan.
- It is noticeable that, while he held his office in the curia through that momentous period of fifty years which witnessed the Councils of Constance and of Basel, and the final restoration of the papacy under Nicholas V., his sympathies were never attracted to ecclesiastical affairs.
- His experiments, in the same year, on the photographic registration of stellar spectra, marked an innovation of a momentous character.
- Powers and instructions as the exigency of a crisis so momentous may require."
- But these years were momentous for Judaism.