1. at high speed; quickly: "she got up and walked swiftly to the door"Similarrapidlyquicklyfastspeedilybrisklyat high speedat full tiltlike the windlike lightningat breakneck speedas fast as one's legs can carry oneas swift as an arrowinformal:double quicknippilylike the clappersliterary:apaceOppositeslowly
▪ without delay; after a very short time:"they acted swiftly in response to the invasion"Similarpromptlyimmediatelyinstantlyinstantaneouslywithout delaypost-hastein a flashin a tricein the wink of an eyein an instantin no time (at all)readilypunctuallymeteoricallysuddenlyabruptlyunhesitatinglyhastilyhurriedlyprecipitatelyheadlonginformal:before you can say Jack Robinsonbefore you can say knifelike a shotlike greased lightningat warp speedp.d.q. (pretty damn quick)lickety-splitin a jiff/jiffyprontoin less than no timeOppositeunhurriedlyin due course