Example : I wonder what the dead person would have done.

Synonyms : dead person, dead soul, deceased, deceased person, decedent

Example : Bygone days.
Dreams of foregone times.
Sweet memories of gone summers.
Relics of a departed era.

Synonyms : bygone, bypast, foregone, gone

Example : He is deceased.
Our dear departed friend.

Synonyms : asleep, at peace, at rest, deceased, gone