Bug spread over cut, unfortunately (9)
I believe the answer is:
eavesdrop
'bug' is the definition.
(thesaurus)
'spread over cut unfortunately' is the wordplay.
'cut' means to remove the last letter.
'unfortunately' indicates anagramming the letters.
'spread'+'over'='spreadover'
'spreadover' with its final letter taken off is 'spreadove'.
'spreadove' with letters rearranged gives 'EAVESDROP'.
(Other definitions for eavesdrop that I've seen before include "Listen at windows" , "Snoop" , "Listen secretly to a private conversation" , "spy" , "Listen in, earwig" .)