grandmistress

From grand +‎ mistress.

grandmistress (plural grandmistresses)

1. (rare) A female grandmaster.
   • 2003, Andy Soltis, Los Voraces 2019: A Chess Novel, page 42:

     The St. Petersburg grandmistress blundered on the 29th move of a Kramnik Sicilian and resigned three moves later.

• It is more common to use grandmaster for both men and women.