masterpiece vs chef-d'oeuvre

masterpiece and chef-d'oeuvre both are nouns.

Word	Noun	Adjective	Verb	Adverb
masterpiece	Yes	No	No	No
chef-d'oeuvre	Yes	No	No	No

As nouns, masterpiece and chef-d'oeuvre are synonyms defined as:

masterpiece and chef-d'oeuvre: the most outstanding work of a creative artist or craftsman

masterpiece (noun)	chef-d'oeuvre (noun)
an outstanding achievement	the most outstanding work of a creative artist or craftsman
the most outstanding work of a creative artist or craftsman