See grimace in Webster's New World Roget's A-Z Thesaurus II
noun
A facial contortion indicating displeasure, disgust, or pain:
face, moue, mouth, pout. (Informal) mug. See express
verb
To contort one's face to indicate displeasure, disgust, or pain, for example:
mouth, mug. Idioms: make a face, make faces. See express
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