oneness vs unity

oneness and unity both are nouns.

Word	Noun	Adjective	Verb	Adverb
oneness	Yes	No	No	No
unity	Yes	No	No	No

As nouns, oneness and unity are synonyms defined as:

oneness (noun)	unity (noun)
the quality of being united into one	the quality of being united into one
	the smallest whole number or a numeral representing this number
	an undivided or unbroken completeness or totality with nothing wanting