Spook correct to enter bog (8)
I believe the answer is:
frighten
'spook' is the definition.
(I've seen this before)
'correct to enter bog' is the wordplay.
'correct' becomes 'right' (synonyms).
'to enter' is an insertion indicator.
'bog' becomes 'fen' (I've seen this in another clue).
'right' put into 'fen' is 'FRIGHTEN'.
(Other definitions for frighten that I've seen before include "Terrify" , "Cow" , "Scare, alarm" , "Cause fear" , "Cause alarm" .)