mourner vs sorrower

mourner and sorrower both are nouns.

Word	Noun	Adjective	Verb	Adverb
mourner	Yes	No	No	No
sorrower	Yes	No	No	No

As nouns, mourner and sorrower are synonyms defined as:

mourner and sorrower: a person who is feeling grief (as grieving over someone who has died)

Other synonyms of mourner include griever, lamenter.

mourner (noun)	sorrower (noun)
a person who is feeling grief (as grieving over someone who has died)	a person who is feeling grief (as grieving over someone who has died)