Partly coincide as regards circuit (7)
I believe the answer is:
overlap
'partly coincide' is the definition.
(I've seen this before)
'regards circuit' is the wordplay.
'regards' becomes 'over' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'circuit' becomes 'lap' ('lap' can be a synonym of 'circuit').
'over'+'lap'='OVERLAP'
'as' acts as a link.
Can you help me to learn more?
(Other definitions for overlap that I've seen before include "Coincide in time or space" , "Imbricate" , "Partially cover" , "Common area of interest" , "Partly cover (another object)" .)