glowering vs glum

glowering and glum both are adjectives.

Word	Noun	Adjective	Verb	Adverb
glowering	No	Yes	No	No
glum	No	Yes	No	No

As adjectives, glowering and glum are synonyms defined as:

Other synonyms of glowering include dark, dour, moody, morose, saturnine, sour, sullen.

glowering (adjective)	glum (adjective)
showing a brooding ill humor	moody and melancholic
	showing a brooding ill humor