game-changer

or game chang·er

[geym-cheyn-jer]
noun
  1. Sports. an athlete, play, etc., that suddenly changes the outcome of a game or contest.
  2. a person or thing that dramatically changes the course, strategy, character, etc., of something: Social media has been a real game-changer in the company’s marketing efforts.

Origin of game-changer

First recorded in 1960–65
Related formsgame-chang·ing, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

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Contemporary Examples of game-changer