Momentous

a.

1.

Of moment or consequence; very important; weighty; as, a momentous decision; momentous affairs.

Adj.

1.

momentous - of very great significance; "deciding to drop the atom bomb was a very big decision"; "a momentous event" Synonyms: big

absolute, ascendant, authoritarian, authoritative, authorized, autocratic, big, big-league, big-name, big-time, bigwig, bigwigged, bustling, charged, charismatic, charming, clothed with authority, commanding, competent, considerable, controlling, crucial, dominant, double-barreled, duly constituted, earthshaking, effective, effectual, efficacious, eminent, empowered, enchanting, epochal, estimable, eventful, ex officio, fraught, full of incident, governing, grand, great, heavyweight, hegemonic, hegemonistic, high-powered, imperative, important, influential, laden, leading, magnetic, major, meaningful, mighty, monocratic, name, of concern, official, personable, persuasive, phenomenal, pivotal, portentous, potent, powerful, preeminent, prestigious, prominent, puissant, ranking, reputable, ruling, self-important, senior, significant, stirring, strong, suasive, substantial, superior, supreme, telling, totalitarian, vital, winning, world-shaking