Crack only found outside civic centre (5)
I believe the answer is:
solve
'crack' is the definition.
(crack can mean to solve or decipher)
'only found outside civic centre' is the wordplay.
'only' becomes 'sole' (synonyms).
'found outside' indicates putting letters inside.
'centre' says to take the centre.
The centre of 'civic' is 'v'.
'sole' enclosing 'v' is 'SOLVE'.
(Other definitions for solve that I've seen before include "Find the answer to a mystery" , "Loves (anag) - to find an answer" , "Unravel (a clue)" , "Unravel (a problem)" , "Find the answer or explanation" .)