showpiece vs peculiarity

showpiece and peculiarity both are nouns.

Word	Noun	Adjective	Verb	Adverb
showpiece	Yes	No	No	No
peculiarity	Yes	No	No	No

As nouns, peculiarity is a hypernym of showpiece; that is, peculiarity is a word with a broader meaning than showpiece:

showpiece: the outstanding item (the prize piece or main exhibit) in a collection
peculiarity: something unusual -- perhaps worthy of collecting

Other hypernyms of showpiece include curio, curiosity, oddity, oddment, rarity.

showpiece (noun)	peculiarity (noun)
the outstanding item (the prize piece or main exhibit) in a collection	something unusual -- perhaps worthy of collecting
	a distinguishing trait
	an odd or unusual characteristic