IPA: //ˈflitli//
KK: /flit-li/
In a quick and agile way; moving or acting swiftly.
The deer fleetly dashed across the field to escape the predator.
Fleetly → It is formed from "fleet" (from Old English "fleot", meaning to float or move swiftly) and the suffix "-ly" (meaning in a manner of). The word "fleetly" means in a swift or quick manner, reflecting the original sense of moving swiftly.
Think of the Old English word for floating or moving swiftly — that's how you can remember that "fleetly" means to do something quickly.