frown vs lour

frown is a noun but lour is not a noun.

Word	Noun	Adjective	Verb	Adverb
frown	Yes	No	Yes	No
lour	No	No	Yes	No

As verbs, frown and lour are synonyms defined as:

frown and lour: look angry or sullen, wrinkle one's forehead, as if to signal disapproval

Other synonyms of frown include glower, lower.

frown (noun)	lour (noun)
a facial expression of dislike or displeasure

frown (verb)	lour (verb)
look angry or sullen, wrinkle one's forehead, as if to signal disapproval	look angry or sullen, wrinkle one's forehead, as if to signal disapproval
	make lower or quieter
	set lower