Unusual year in bustling capital (8)
I believe the answer is:
atypical
'unusual' is the definition.
(synonyms)
'year in bustling capital' is the wordplay.
'year' becomes 'y'.
'in' means one lot of letters goes inside another.
'bustling' indicates anagramming the letters (letters bustle around).
'capital' anagrammed gives 'atpical'.
'y' placed into 'atpical' is 'ATYPICAL'.
(Other definitions for atypical that I've seen before include "Irregular" , "Not as expected" , "Unrepresentative" , "Nonconforming" , "Unusual" .)