Decelerating refers to slowing down, slowing the pace or reducing the speed of a particular activity or process. Synonyms for decelerating include slowing, easing off, slackening, dampening, downshifting, petering out, lagging behind, and decreasing speed. Other way to express the idea of decelerating is to say that something is coming to a halt, losing momentum, or fading away. These synonyms can be useful in different contexts such as driving, sports, or even in business when talking about reducing the speed of a project or initiative. Ultimately, the choice of synonym will depend on the context and the intended meaning of the statement.