Electrical work interrupted by the scornful (9)
I believe the answer is:
withering
'scornful' is the definition.
(thesaurus)
'electrical work interrupted by the' is the wordplay.
'electrical work' becomes 'wiring' (I've seen this before).
'interrupted by' indicates putting letters inside.
'wiring' enclosing 'the' is 'WITHERING'.
(Other definitions for withering that I've seen before include "Devastating" , "Supercilious" .)