vacuous vs hollow

vacuous is not a noun while hollow is a noun.

Word	Noun	Adjective	Verb	Adverb
vacuous	No	Yes	No	No
hollow	Yes	Yes	Yes	No

As adjectives, vacuous and hollow are synonyms defined as:

Other synonyms of vacuous include empty.

vacuous (noun)	hollow (noun)
	a depression hollowed out of solid matter
	a small valley between mountains
	a cavity or space in something

vacuous (adjective)	hollow (adjective)
devoid of matter	not solid; having a space or gap or cavity
devoid of intelligence or thought	lacking in substance or character
devoid of significance or force	devoid of significance or force
	as if echoing in a hollow space

vacuous (verb)	hollow (verb)
	remove the interior of
	remove the inner part or the core of