mourner vs unfortunate person

mourner and unfortunate person both are nouns.

Word	Noun	Adjective	Verb	Adverb
mourner	Yes	No	No	No
unfortunate person	Yes	No	No	No

As nouns, unfortunate person is a hypernym of mourner; that is, unfortunate person is a word with a broader meaning than mourner:

mourner: a person who is feeling grief (as grieving over someone who has died)
unfortunate person: a person who suffers misfortune

Other hypernyms of mourner include unfortunate.

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