Superlative form of holy: most holy.; most sacred.(adjective)
Superlative form of holey: most holey.; most full of holes.(adjective)
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Use "holiest" in a sentence
"And hallow'd like the land, in holiest beauty lies."
"They even call our holiest ceremony a trance dance and see us entering a kind of dreamscape."
"I invite comment here because there are differing opinions surrounding the origins of Christmas, the so-called holiest day on the Christian calendar."