moment vs momentous

moment is a noun but momentous is not a noun.

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

moment (noun)	momentous (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

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