The Oxford Thesaurus An A-Z Dictionary of Synonyms - rapidly adv.

1) quickly, fast, swiftly, speedily, briskly, expeditiously, like a shot, at the speed of light, double-quick, at full speed, like one possessed, at a gallop, tantivy, Colloq like blazes, like (greased) lightning, US lickety-split, Slang like a bat out of hell, like mad: He cycled down the High Street as rapidly as he could go. 2) promptly, instantly, instantaneously, instanter, without delay, at once, straight away, right away, in a moment, in a trice, like a shot, in a wink, in (less than) no time, double-quick, in a flash, at the speed of light, before you (can) turn around, Colloq in a jiffy, in two shakes (of a lamb's tail) , like (greased) lightning, before you can say 'Jack Robinson', US and Canadian (right) off the bat, lickety-split, Slang like a bat out of hell: When I mentioned that you were coming, she left rapidly.