Fast-moving is a commonly used adjective to describe things that move quickly or at a rapid pace. However, there are many synonyms that can be used instead of fast-moving. These synonyms include swift, rapid, speedy, quick, hasty, nimble, brisk, fleet, and expeditious. Each of these words can be used to describe something that moves quickly, and the choice of which one to use may depend on the context and the desired tone of the writing. By expanding your vocabulary and using synonyms instead of the same words repeatedly, you can create more interesting and engaging writing that captures your readers' attention.