momentous
/moʊˈmɛn.təs/ adjective C1- Outstanding in importance, of great consequence.
From the library
The intelligence with which Lestrade greeted us was so momentous and so unexpected, that we were all three fairly dumfoundered.
This formal announcement, which implied or appeared to imply, the approval of all the persons concerned in this momentous affair, had been preceded by a scene to which our readers must be admitted.
Until that momentous day arrives, I will continue to uncover the ancient secrets locked within the continental ice.
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