forty winks

Example: “I'm going to catch forty winks before dinner.”

Origin: "Wink" has meant a stretch of sleep since at least the 1300s, with William Langland's Piers Plowman (1377) already using "thenne wakede I of my wink." The specific pairing "forty winks" for a short nap surfaces in print by 1821, in English cook William Kitchiner's The Art of Invigorating and Prolonging Life, and again in Pierce Egan's 1828 Tom and Jerry. Why forty specifically was chosen, rather than any other number, is genuinely unresolved. A tongue-in-cheek explanation printed in Punch magazine in 1872 jokes that dozing off partway through the Church of England's tedious Thirty-Nine Articles would naturally produce "forty winks" — one wink past the Articles' own count — but the real phrase had already been in print for decades by then, ruling the joke out as an actual origin. "Forty" more likely just carried its old, common role in English and biblical tradition as a stand-in for "a substantial but unspecified number," the same job it does in "forty days and forty nights."