emptiness vs vacancy

emptiness and vacancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
emptiness	Yes	No	No	No
vacancy	Yes	No	No	No

As nouns, emptiness and vacancy are synonyms defined as:

Other synonyms of emptiness include vacuum, void.

As nouns, vacancy is a hyponym of emptiness; that is, vacancy is a word with a more specific, narrower meaning than emptiness:

Other hyponyms of emptiness include blankness, hollowness, vacuity, vacuum.

emptiness (noun)	vacancy (noun)
the quality of being valueless or futile	an empty area or space
an empty area or space	being unoccupied
the state of containing nothing
having an empty stomach