Take place of officer knocked over by bounder (5)
I believe the answer is:
occur
'take place' is the definition.
(synonyms)
'officer knocked over by bounder' is the wordplay.
'officer' becomes 'co' (Commanding Officer abbreviation).
'knocked over' shows that the letters should be reversed in order.
'by' is a charade indicator (letters next to each other).
'bounder' becomes 'cur' (I've seen this in another clue).
'co' backwards is 'oc'.
'oc'+'cur'='OCCUR'
'of' is the link.
(Other definitions for occur that I've seen before include "Happen - to come to mind" , "crop up" , "found" , "exist" , "Spring to mind" .)