high-flown vs rarefied

high-flown and rarefied both are adjectives.

Word	Noun	Adjective	Verb	Adverb
high-flown	No	Yes	No	No
rarefied	No	Yes	No	No

As adjectives, high-flown and rarefied are synonyms defined as:

high-flown and rarefied: of high moral or intellectual value; elevated in nature or style

Other synonyms of high-flown include elevated, exalted, grand, high-minded, idealistic, lofty, noble-minded, rarified, sublime.

high-flown (adjective)	rarefied (adjective)
of high moral or intellectual value; elevated in nature or style	of high moral or intellectual value; elevated in nature or style
pretentious (especially with regard to language or ideals)	having low density