Guided a jerk over castle (7)
I believe the answer is:
citadel
'castle' is the definition.
(thesaurus)
'guided a jerk over' is the wordplay.
'guided' becomes 'led' ('lead' can be a synonym of 'guide').
'jerk' becomes 'tic' (I've seen this before).
'over' says the letters should be written backwards.
'led'+'a'+'tic'='ledatic'
'ledatic' in reverse letter order is 'CITADEL'.
(Other definitions for citadel that I've seen before include "where Salvationists meet" , "Fort, fastness" , "Fortress -- dialect (anag)" , "Structure in place to protect" , "Highly-secure building" .)