Unusual year in transformed capital (8)
I believe the answer is:
atypical
'unusual' is the definition.
(similar in meaning)
'year in transformed capital' is the wordplay.
'year' becomes 'y'.
'in' means one lot of letters goes inside another.
'transformed' indicates an anagram.
'capital' is an anagram of 'atpical'.
'y' put within 'atpical' is 'ATYPICAL'.
(Other definitions for atypical that I've seen before include "Nonconforming" , "Deviating from what is usual or common" , "Odd" , "Not conforming to a norm or average" , "out of character" .)