Playful movement (6)
I believe the answer is:
frolic
'playful movement' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for frolic that I've seen before include "Antic, romp" , "Cut capers" , "Play about in lively cheerful way" , "'Frisk, gambol (6)'" , "Caper, gambol" .)