grimacing

/G R IH1 M AH0 S IH0 NG/
verb
  1. 1

    To make grimaces; to distort one's face; to make faces.

noun
  1. 1

    The act of making a grimace.

Source: https://en.wiktionary.org/wiki/grimace, https://en.wiktionary.org/wiki/grimacing