swift (n.) Look up swift at Dictionary.com
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).
swift (adj.) Look up swift at Dictionary.com
Old English swift "moving quickly," perhaps originally "turning quickly," from Proto-Germanic swip- (see swivel (n.)). Related: Swiftly; swiftness.