Nouns

(n)dead person, dead soul, deceased person, deceased, decedent, departedsomeone who is no longer alive“I wonder what the dead person would have done”

Adjectives

(s)bygone, bypast, departed, foregone, gonewell in the past; former“bygone days”, “dreams of foregone times”, “sweet memories of gone summers”, “relics of a departed era”
(s)asleep, at peace, at rest, deceased, departed, gonedead“he is deceased”, “our dear departed friend”