dead person vs decedent

dead person and decedent both are nouns.

Word	Noun	Adjective	Verb	Adverb
dead person	Yes	No	No	No
decedent	Yes	No	No	No

As nouns, dead person and decedent are synonyms defined as:

Other synonyms of dead person include dead soul, deceased, deceased person, departed.

dead person (noun)	decedent (noun)
someone who is no longer alive	someone who is no longer alive