masterstroke

UK: /ˈmɑːstə^rstrəʊk/

US: /ˈmæstɚˌstroʊk/

US: (mas′tər strōk′, mä′stər-)

WordReference Random House Learner's Dictionary of American English © 2025

mas•ter•stroke /ˈmæstɚˌstroʊk/   n. [countable]

1. an extremely skillful or effective action:
   planned his masterstroke to catch his opponent off guard.

WordReference Random House Unabridged Dictionary of American English © 2025

mas•ter•stroke  (mas′tər strōk′, mä′stər-), n. 

1. a masterly action or achievement;
   an extremely skillful or effective action:
   War was avoided by a masterstroke of diplomacy.

Also, mas′ter stroke′. 

• master + stroke¹ 1670–80

Collins Concise English Dictionary © HarperCollins Publishers::

masterstroke / ˈmɑːstəˌstrəʊk/ noun

1. an outstanding piece of strategy, skill, talent, etc