Crooked city alarms me when rebuilt (12)
I believe the answer is:
asymmetrical
'crooked' is the definition.
(I know that crooked can be written as asymmetrical)
'city alarms me when rebuilt' is the wordplay.
'when rebuilt' is an anagram indicator.
'city'+'alarms'+'me'='cityalarmsme'
'cityalarmsme' is an anagram of 'ASYMMETRICAL'.
(Other definitions for asymmetrical that I've seen before include "Not even" , "Irregular in outline" , "a gymnast would use such bars" , "Crooked" .)