momentous Meaning, Definition & Usage

  1. adjective satellite of very great significance
    • deciding to drop the atom bomb was a very big decision
    • a momentous event

WordNet

Mo*men"tous adjective
Etymology
Cf. L. momentosus rapid, momentary.
Definitions
  1. Of moment or consequence; very important; weighty; as, a momentous decision; momentous affairs. -- Mo*men"tous*ly, adv. -- Mo*men"tous*ness, n.

Webster 1913