slipper (n.)youdaoicibaDictYouDict[slipper 词源字典]
type of loose, light indoor footwear, late 15c., agent noun from slip (v.), the notion being of a shoe that is "slipped" onto the foot. Old English had slypescoh "slipper," literally "slip-shoe."[slipper etymology, slipper origin, 英语词源]