Fidgety - it's ever changing! (7)
I believe the answer is:
restive
'fidgety' is the definition.
(synonyms)
'it's ever changing' is the wordplay.
'changing' indicates anagramming the letters.
'its'+'ever'='itsever'
'itsever' anagrammed gives 'RESTIVE'.
(Other definitions for restive that I've seen before include "Resisting control, nervous or impatient" , "Impatient - jumpy" , "It veers around, resisting control" , "Unsettled" , "Impatient of authority" .)