Compare Daco-Romanian copil. Probably from South Slavic *kopylъ(“shoot, sprout; bastard”) (compare Serbo-Croatian ко̏пиле/kȍpile, Bulgarian ко́пеле(kópele)), from *kopati(“to dig, cultivate”). Also borrowed into Albanian kopil, Byzantine Greek κόπελος(kópelos). Alternatively an ultimately paleo-Balkan substratum word.