glower vs grimace

glower and grimace both are nouns.

Word	Noun	Adjective	Verb	Adverb
glower	Yes	No	Yes	No
grimace	Yes	No	Yes	No

As verbs, grimace is a hypernym of glower; that is, grimace is a word with a broader meaning than glower:

glower: look angry or sullen, wrinkle one's forehead, as if to signal disapproval
grimace: contort the face to indicate a certain mental or emotional state

Other hypernyms of glower include make a face, pull a face.

glower (noun)	grimace (noun)
an angry stare	a contorted facial expression

glower (verb)	grimace (verb)
look angry or sullen, wrinkle one's forehead, as if to signal disapproval	contort the face to indicate a certain mental or emotional state
look at with a fixed gaze