Ridiculous to search around bog after setback (7)
I believe the answer is:
foolish
'ridiculous' is the definition.
(similar in meaning)
'search around bog after setback' is the wordplay.
'search' becomes 'fish' (fishing is a kind of searching).
'around' is an insertion indicator.
'bog' becomes 'loo' (I've seen this before).
'after setback' says the letters should be written in reverse.
'loo' written backwards gives 'ool'.
'fish' enclosing 'ool' is 'FOOLISH'.
'to' is the link.
(Other definitions for foolish that I've seen before include "Unwise or ridiculous" , "Not very bright" , "Half-baked" , "Imprudent" , "Silly, lacking common sense" .)