decedent vs dead soul

decedent and dead soul both are nouns.

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

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

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

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