hollow vs vacuous

hollow is a noun but vacuous is not a noun.

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

As adjectives, hollow and vacuous are synonyms defined as:

Other synonyms of hollow include empty.

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

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

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