grandiosity vs expressive style

grandiosity and expressive style both are nouns.

Word	Noun	Adjective	Verb	Adverb
grandiosity	Yes	No	No	No
expressive style	Yes	No	No	No

As nouns, expressive style is a hypernym of grandiosity; that is, expressive style is a word with a broader meaning than grandiosity:

grandiosity: high-flown style; excessive use of verbal ornamentation
expressive style: a way of expressing something (in language or art or music etc.) that is characteristic of a particular person or group of people or period

Other hypernyms of grandiosity include style.

grandiosity (noun)	expressive style (noun)
high-flown style; excessive use of verbal ornamentation	a way of expressing something (in language or art or music etc.) that is characteristic of a particular person or group of people or period