Guide dog charge demanded by landlord? Could be shocking (6,7)
I believe the answer is:
direct current
'could be shocking' is the definition.
(direct current might give you an electric shock)
'guide dog charge demanded by landlord?' is the wordplay.
'guide' becomes 'direct' (synonyms).
'dog' becomes 'cur' (both can mean a despicable person).
'charge demanded by landlord?' becomes 'rent' (rent for property).
'direct'+'cur'+'rent'='DIRECT CURRENT'
(Other definitions for direct current that I've seen before include "DC in full" , "Electricity flow from, eg, battery" , "Electrical flow in one direction only" , "potentially shocking!" , "Electrically, DC" .)