i Register
In some senses, decease is marked as formal, archaic. Watch for register when choosing this word.
noun
Death, departure from life.
So should that beauty which you hold in lease Find no determination: then you were Yourself again after yourself's decease […]
I thought about my predecessor, who had died of drink and smoke; and I could have wished he had been so good as to live, and not bother me with his decease.
verb
To die.
After which usurped victorie, he presently deceased: and partly through the excessive joy he thereby conceived.
To cause to die.