When it comes to finding synonyms for the word "fast", there are plenty of options to choose from. Some popular options include rapid, swift, speedy, hasty, and quick. These synonyms are often used to describe things that move quickly or happen quickly, such as a fast car or a fast-paced game. Other synonyms for fast might include brisk, nimble, agile, or fleet-footed, which are often used to describe someone who is moving quickly or who has a quick reaction time. Ultimately, the right synonym for fast will depend on the context in which it is used and the precise meaning that the writer or speaker wants to convey.