mourner vs weeper

mourner and weeper both are nouns.

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

As nouns, weeper is a hyponym of mourner; that is, weeper is a word with a more specific, narrower meaning than mourner:

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

Other hyponyms of mourner include bearer, pallbearer, wailer.

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