conservative vs buttoned-down

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

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

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

Other synonyms of conservative include button-down.

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

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