fastHe drives too fast for my liking.
quicklyThe problem needs to be solved as quickly as possible.
swiftlyHe left and returned swiftly.
precipitouslyShare prices dropped precipitously on the economic news.
apaceformal or literaryThe building went on apace.
in a flashinformalI'll be back in a flash.
at breakneck speedThe crew has to work at breakneck speed to make repairs and adjustments to the racing car.
in the twinkling of an eyeold-fashionedThose little ones grow into adults in the twinkling of an eye.