buttoned-down vs conservative

buttoned-down is not a noun while conservative is a noun.

Word	Noun	Adjective	Verb	Adverb
buttoned-down	No	Yes	No	No
conservative	Yes	Yes	No	No

As adjectives, buttoned-down and conservative are synonyms defined as:

Other synonyms of buttoned-down include button-down.

buttoned-down (noun)	conservative (noun)
	a person who is reluctant to accept changes and new ideas

buttoned-down (adjective)	conservative (adjective)
unimaginatively conventional	resistant to change, particularly in relation to politics or religion
	unimaginatively conventional
	conforming to the standards and conventions of the middle class
	avoiding excess
	having social or political views favoring conservatism