masterpiece

noun

1. A piece of work that has been given much critical praise, especially one that is considered the greatest work of a person's career.

   “The design, when finally developed, was a slight disappointment to Monsieur Deplis, who had suspected Icarus of being a fortress taken by Wallenstein in the Thirty Years' War, but he was more than satisfied with the execution of the work, which was acclaimed by all who had the privilege of seeing it as Pincini's masterpiece.”

2. A work of outstanding creativity, skill or workmanship.

   “Masterpieces are not completed, they are abandoned.”

   ““‘Man is amazing, but he is not a masterpiece,’ he said, keeping his eyes fixed on the glass case. ‘Perhaps the artist was a little mad. […]’”

   “It would hardly be an overstatement to describe Drummond's next design as an outstanding British locomotive class, and possibly his masterpiece.”

   “It was replaced by a New Euston, "bold in design and layout and in keeping with a new railway era". Betjeman was unmoved, describing it tersely as "no masterpiece" and noting that its lack of platform seating made it an "inhuman structure" which seemed to ignore passengers.”

3. A work created in order to qualify as a master craftsman and member of a guild.