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English definition of “momentous”

momentous

adjective     /məˈmen.təs/ US  /-t̬əs/
very important because of effects on future events: the momentous news of the president's death Whether or not to move overseas was a momentous decision for the family.Very important or urgent momentously     /-li/ adverb Very important or urgent momentousness     /-nəs/ noun [U] ImportanceUseful or advantageous
(Definition of momentous adjective from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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