1 vs unity

1 and unity both are nouns.

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

As nouns, 1 and unity are synonyms defined as:

1 and unity: the smallest whole number or a numeral representing this number

Other synonyms of 1 include ace, I, one, single.

1 (noun)	unity (noun)
the smallest whole number or a numeral representing this number	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

1 (adjective)	unity (adjective)
used of a single unit or thing; not two or more