fashion vs high style

fashion and high style both are nouns.

Word	Noun	Adjective	Verb	Adverb
fashion	Yes	No	Yes	No
high style	Yes	No	No	No

As nouns, high style is a hyponym of fashion; that is, high style is a word with a more specific, narrower meaning than fashion:

fashion: the latest and most admired style in clothes and cosmetics and behavior
high style: trend-setting fashions

Other hyponyms of fashion include cult of personality, cut, haute couture, high fashion, craze, cult, fad, furor, furore, rage, retro.

fashion (noun)	high style (noun)
characteristic or habitual practice	trend-setting fashions
consumer goods (especially clothing) in the current mode
how something is done or how it happens
the latest and most admired style in clothes and cosmetics and behavior

fashion (verb)	high style (verb)
make out of components (often in an improvising manner)