The term 'light on one's feet' is often used to describe someone who is NIMBLE, SPRY, and AGILE. NIMBLE is a 6-letter word meaning 'quick and light in movement or action; AGILE.' SPRY is a 4-letter word meaning 'active; lively; brisk; AGILE.' AGILE is a 5-letter word meaning 'able to move quickly and easily; lithe; active; NIMBLE.' Therefore, the term 'light on one's feet' can be used to describe someone who is quick, active, and able to move easily.