living dead vs deceased person

living dead and deceased person both are nouns.

Word	Noun	Adjective	Verb	Adverb
living dead	Yes	No	No	No
deceased person	Yes	No	No	No

As nouns, deceased person is a hypernym of living dead; that is, deceased person is a word with a broader meaning than living dead:

living dead: a dead body that has been brought back to life by a supernatural force
deceased person: someone who is no longer alive

Other hypernyms of living dead include dead person, dead soul, deceased, decedent, departed.

living dead (noun)	deceased person (noun)
a dead body that has been brought back to life by a supernatural force	someone who is no longer alive