swiftyoudaoicibaDictYouDict[swift 词源字典]
swift: [OE] The etymological meaning of swift appears to be ‘moving along a course’; ‘speed’ is a secondary development. It goes back ultimately to the prehistoric Germanic base *swei- ‘swing, bend’, which also produced English sweep, swivel [14], and the long defunct swive ‘copulate with’ (a descendant of Old English swīfan ‘move in a course’). Its use as a name for the fast-flying swallow-like bird dates from the 17th century.
=> sweep, swivel[swift etymology, swift origin, 英语词源]
swift (adj.)youdaoicibaDictYouDict
Old English swift "moving quickly," perhaps originally "turning quickly," from Proto-Germanic swip- (see swivel (n.)). Related: Swiftly; swiftness.
swift (n.)youdaoicibaDictYouDict
type of bird (several species of the family Cypselidæ, resembling swallows), 1660s, from swift (adj.) in reference to its swift flight. Regarded as a bird of ill-omen, if not downright demonic, probably for its shrill cry. The name earlier had been given to several small fast lizards (1520s).