exhibitionism vs ostentation

exhibitionism and ostentation both are nouns.

Word	Noun	Adjective	Verb	Adverb
exhibitionism	Yes	No	No	No
ostentation	Yes	No	No	No

As nouns, ostentation is a hypernym of exhibitionism; that is, ostentation is a word with a broader meaning than exhibitionism:

exhibitionism: extravagant and conspicuous behavior intended to attract attention to yourself
ostentation: a gaudy outward display

Other hypernyms of exhibitionism include fanfare, flash.

exhibitionism (noun)	ostentation (noun)
the perverse act of exposing and attracting attention to your own genitals	pretentious or showy or vulgar display
extravagant and conspicuous behavior intended to attract attention to yourself	lack of elegance as a consequence of being pompous and puffed up with vanity
	a gaudy outward display