Move restlessly (6)
I believe the answer is:
fidget
'move restlessly' is the definition.
(synonyms)
This is all the clue.
(Other definitions for fidget that I've seen before include "Wriggle" , "Make small restless or uneasy movements" , "Make small movements through nervousness or impatience" , "Restless person" , "Make nervous movements of the hands" .)