momentous vs moment

momentous is not a noun while moment is a noun.

Word	Noun	Adjective	Verb	Adverb
momentous	No	Yes	No	No
moment	Yes	No	No	No

momentous (noun)	moment (noun)
	having important effects or influence
	the n-th moment of a distribution is the expected value of the n-th power of the deviations from a fixed value
	a turning force produced by an object acting at a distance (or a measure of that force)
	a particular point in time
	an indefinitely short time
	at this time

momentous (adjective)	moment (adjective)
of very great significance