Purple prose is a noun phrase used to describe prose that is showy, elaborate, or overemotional. The term is used particularly when the writing gets in the way of the reader’s experience. It does not need quotation marks or a hyphen.
The term is attributed to the Roman poet Horace, who died in 8 BC. The Latin words professis purpureus have been translated as purple patches, purple cloth, or purple prose. In that time period purple was specifically associated with royalty.