Uniform worn in citadel (9)
I believe the answer is:
identical
'uniform' is the definition.
(I've seen this before)
'worn in citadel' is the wordplay.
'worn' indicates an anagram (worn can mean damaged).
'in'+'citadel'='incitadel'
'incitadel' is an anagram of 'IDENTICAL'.
(Other definitions for identical that I've seen before include "Aid client to be the very same" , "Like two peas in a pod" , "as B and B" , "not distinguished" , "Equal" .)