Error - stop assuming end of nose produces bogey (7)
I believe the answer is:
bugbear
'bogey' is the definition.
(thesaurus)
'error stop assuming end of nose' is the wordplay.
'error' becomes 'bug' (computer error).
'stop' becomes 'bar' (bar can mean to stop or prevent).
'assuming' indicates putting letters inside (inserted letters are taken in or assumed).
'of nose' says to take the initial letters (I've seen 'nose' mean this (nose can mean the front of something)).
The first letter of 'end' is 'e'.
'bar' enclosing 'e' is 'bear'.
'bug'+'bear'='BUGBEAR'
'produces' acts as a link.
(Other definitions for bugbear that I've seen before include "pet hate" , "[BOGYMAN]" , "Cause of excessive anxiety" , "Object of obsessive, foolish fear" , "Obsessive idea" .)