costning

From Middle English costning, costnunge, from Old English costnung (“temptation, testing, trial, tribulation”), from Old English costnian, variant of Old English costian (“to tempt, try, prove, examine”), from Proto-Germanic *kustōną (“to try, taste”), from Proto-Indo-European *ǵews- (“to enjoy, taste”), equivalent to cost + -ing. Cognate with German kosten (“to taste”). Related to choose.

来源：wiktionary