The word dead and the word deceased can mean the same thing and so they are synonyms.
He wasn't always Dead, he was once living and breathing like you and me.
Deceased is ended or dead.
An antonym for deceased is dead.
expired, dead, deceased, gone to heaven,
Having finished the course of life; dead; deceased., A dead person; one deceased.
i was mortified when i saw the dead bird laying on the floor!
Alonso fainted when he saw his father dead
The dead deer started to decay.
The scientist examined the baleen from the dead whale.
Bluepaw wailed in dismay at the sight of her dead mother.
The mould was sloughed from the walls with a chemical spray
Deceased. A discommodiously dead dragon.