Chef-d'oeuvre and Masterwork

Chef-d'oeuvre noun - The most outstanding work of a creative artist or craftsman.

Masterwork and chef-d'oeuvre are semantically related in good topic. In some cases you can use "Masterwork" instead a noun phrase "Chef-d'oeuvre".

Masterwork noun - Something (as a work of art) that is a great achievement and often its creator's greatest achievement.

Chef-d'oeuvre and masterwork are semantically related in good topic. You can use "Chef-d'oeuvre" instead a noun "Masterwork".