Chef d’oeuvre
Chef d’oeuvre /ˌʃeɪdˈɜː.vrə/ US /-ˈɝː-/ (noun)
a great work of art, masterpiece, stroke of genius, tour de force, Chef-d’oeuvre:
The Last Supper by Leonardo da Vinci is one of the chefs d’oeuvre in painting.
The painting could have been included as a praiseworthy chef d’oeuvre only if you had exhibited it publicly.
Artists can reach their zenith if they increase the quality and quantity of their chefs d’oeuvre.