What is the Latin word for momentous?

The usual Latin words for “momentous” are magnus, gravis, permagnus; also negōtium. The right choice depends on the sense; see the distinctions below.

English → Latin

“momentous” in Latin

magnusgreat, large, big; (of things) vast, extensive, spacious (of physical size or quantity); great, grand, mighty, noble, lo gravisheavy; pregnant; troublesome, hard permagnusvery great; very large negōtiumbusiness, employment, occupation, affair; difficulty, pains, trouble, labor; matter, thing (= πρᾶγμα (prâgma))

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

momentous

magni or maximi momenti: gravis (gravior, gravissimus): permagnus (e.g., negotium, Cic.).

Quick answer

What is the Latin word for momentous?: The usual Latin words for “momentous” are magnus, gravis, permagnus; also negōtium. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.