Quickly is a word that is used often in the English language, but sometimes, it can become repetitive in writing or conversation. Here are some synonyms that can be used in its place. Rapidly, speedily, swiftly, promptly, briskly, hurriedly, expeditiously, hastily, fleetly, nimbly, expeditiously, pronto, dexterously, pronto, agilely, abruptly, blisteringly, immediately, instantaneously, snappily, and summarily. These synonyms not only make your writing or conversation more interesting, but they also add depth to the meaning by providing a new perspective on the concept of quickly.