Swift
Old English (as an adjective), from the Germanic base of Old English swīfan ‘move in a course, sweep’. The bird name dates from the mid 17th century.
wiktionary
From Middle English swift, from Old English swift(“swift; quick”), from Proto-Germanic *swiftaz(“swift; quick”), from Proto-Indo-European *(s)weyp-(“to twist; wind around”). Cognate with Icelandic svipta(“to pull quickly”), Old English swīfan(“to revolve, sweep, wend, intervene”). More at swivel.
etymonline
swift (adj.)
Old English swift "moving quickly," perhaps originally "turning quickly," from Proto-Germanic swip- (see swivel (n.)). Related: Swiftly; swiftness.
swift (n.)
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).
