c.1500, transitive, "to move gently" (through the air), probably from Middle Dutch or Middle Low German, ultimately from wachten "to guard" (perhaps via notion of a ship that guards another as it sails), related to waken "rouse from sleep," from Proto-Germanic *waht- (see wake, n.1). Possibly influenced by northern dialect waff "cause to move to and fro" (1510s), a variant of wave. Intransitive sense from 1560s. Related: Wafted; wafting.