unassuming vs retiring

unassuming and retiring both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unassuming	No	Yes	No	No
retiring	No	Yes	No	No

As adjectives, unassuming and retiring are synonyms defined as:

unassuming (adjective)	retiring (adjective)
not arrogant or presuming	not arrogant or presuming
	of a person who has held and relinquished a position or office
	reluctant to draw attention to yourself