Partly cover more than circuit (7)
I believe the answer is:
overlap
'partly cover' is the definition.
(I've seen this before)
'more than circuit' is the wordplay.
'more than' becomes 'over' (I've seen this before).
'circuit' becomes 'lap' ('lap' can be a synonym of 'circuit').
'over'+'lap'='OVERLAP'
(Other definitions for overlap that I've seen before include "Coincide in part" , "Extend on top of" , "Rest one on another" , "Partially cover" , "Partly cover - a plover (anag)" .)