cheap

As a noun, from Middle English chep, from Old English cēap (“trade, market, value”), from Proto-West Germanic *kaup. As a verb, from Middle English chepen, from Old English ċēapian (“to buy, bargain, trade”), from Proto-West Germanic *kaupōn, from Proto-Germanic *kaupōną, a verbal derivative of *kaupô (“trader”), from Latin caupō.

The adjective originated as a shortening of Middle and Early Modern English good cheap, literally “good purchase” (as in “that was good cheap”, i.e. “that was [a] good purchase”). Compare Dutch goedkoop, French bon marché.

Cognates

Cognate with Scots chepe (“to sell”), chape (“sale price”), North Frisian keap (“purchase”), West Frisian keap (“purchase, buy, acquisition”), Dutch koop (“buy, purchase, deal”), kopen (“to buy, purchase, shop”), Low German kopen (“to buy”), German Kauf (“trade, traffic, bargain, purchase, buy”), kaufen (“to buy”), Swedish köp (“bargain, purchase”), köpa (“to buy, purchase”), Norwegian Nynorsk kjøpa (“to buy, purchase”), Icelandic kaup (“purchase, bargain”), kaupa (“to purchase”); also borrowed as Finnish kauppa (“shop, trade”), Russian купить (kupitʹ, “to purchase”), Old Church Slavonic коупити (kupiti, “to purchase”), Bulgarian ку́пя (kúpja, “to purchase”), Serbo-Croatian купити (“to purchase”), Czech koupit (“to purchase”), Polish kupić (“to purchase”).