sanitariness vs hygiene

sanitariness and hygiene both are nouns.

Word	Noun	Adjective	Verb	Adverb
sanitariness	Yes	No	No	No
hygiene	Yes	No	No	No

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

Other hyponyms of sanitariness include antisepsis, asepsis, sterileness, sterility, sanitation.

sanitariness (noun)	hygiene (noun)
the state of being conducive to health	the science concerned with the prevention of illness and maintenance of health
	a condition promoting sanitary practices