Lament for one in city (5)
I believe the answer is:
elegy
'lament' is the definition.
('elegy' can be a synonym of 'lament')
'for one in city' is the wordplay.
'for one' becomes 'eg' (I've seen this in other clues).
'in' is an insertion indicator.
'city' becomes 'ely' (I've seen this before).
'eg' placed within 'ely' is 'ELEGY'.
(Other definitions for elegy that I've seen before include "Sad words" , "Poetic lament for the dead" , "Sad work" , "Poetic lament (in a country churchyard?)" , "Work by Gray?" .)