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.
The antonym for deceased is living or alive.
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!
The dead deer started to decay.
Alonso fainted when he saw his father dead
The mould was sloughed from the walls with a chemical spray
Bluepaw wailed in dismay at the sight of her dead mother.
The scientist examined the baleen from the dead whale.
Deceased. A discommodiously dead dragon.