departed vs deceased

departed and deceased both are nouns.

Word	Noun	Adjective	Verb	Adverb
departed	Yes	Yes	No	No
deceased	Yes	Yes	No	No

As adjectives, departed and deceased are synonyms defined as:

Other synonyms of departed include asleep, at peace, at rest, gone.

As nouns, departed and deceased are synonyms defined as:

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

departed (noun)	deceased (noun)
someone who is no longer alive	someone who is no longer alive

departed (adjective)	deceased (adjective)
dead	dead
well in the past; former