high-flown vs high-sounding

high-flown and high-sounding both are adjectives.

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

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

high-flown and high-sounding: pretentious (especially with regard to language or ideals)

Other synonyms of high-flown include inflated.

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