Top bloke has reserve (6)
I believe the answer is:
bodice
'top' is the definition.
(bodice is a kind of top)
'bloke has reserve' is the wordplay.
'bloke' becomes 'bod' (I've seen this in other clues).
'has' says to put letters next to each other.
'reserve' becomes 'ice' (I've seen this before).
'bod'+'ice'='BODICE'
(Other definitions for bodice that I've seen before include "Close-fitting top of a dress" , "Old undergarment is visible" , "Spencer" , "Top half of a dress" , "Upper half of dress" .)