grandmaster

/G R AE1 N D M AE1 S T ER0/
noun
  1. 1

    A player of the highest rank, as determined by FIDE, with an Elo rating of at least 2500.

noun
  1. 1

    A master in a field, whose skills or accomplishments exceed those of other masters.

Source: https://en.wiktionary.org/wiki/Grandmaster, https://en.wiktionary.org/wiki/grandmaster