"Fleetlier" is a word used to describe something that moves quickly and swiftly. There are several synonyms for "fleetlier" that can be used to describe this movement. Some of these include "faster," "swifter," "more rapid," "accelerated," "speedier," "nimble," "lightning-fast," and "galloping." These words can be used interchangeably with "fleetlier" to convey the same meaning. It's important to choose the right synonym based on the context and tone of the sentence. For example, "nimble" may be used to describe the graceful movement of a gymnast, while "speedier" may be used to describe the quick movement of a car on a race track.