The phrase "the quick" can have a variety of synonyms depending on the context in which it is used. Some possible synonyms for "the quick" include agile, swift, fleet-footed, nimble, speedy, and fast-moving. These terms all suggest a sense of quickness and efficiency. Other possible synonyms might include brisk, sprightly, lively, alert, and quick-witted. These terms all suggest a sense of vitality and liveliness, and could be used to describe someone who is both physically and mentally quick. Ultimately, the choice of synonym will depend on the specific context, as well as the tone and style of the writing itself.