Perpetual movement of giant levers (11)
I believe the answer is:
everlasting
'perpetual' is the definition.
(synonyms)
'movement of giant levers' is the wordplay.
'movement of' indicates anagramming the letters (I've seen 'movement' mean this (letters move around)).
'giant'+'levers'='giantlevers'
'giantlevers' is an anagram of 'EVERLASTING'.
(Other definitions for everlasting that I've seen before include "description of the rest Romeo set up here?" , "Unending" , "Eternal" , "Timeless" , "permanent" .)