Dress right for a boy (6)
I believe the answer is:
robert
'a boy' is the definition.
(I've seen this before)
'dress right' is the wordplay.
'dress' becomes 'robe' (robing is a kind of dressing).
'right' becomes 'rt'.
'robe'+'rt'='ROBERT'
'for' is the link.
(Other definitions for robert that I've seen before include "Boy" , "-- Browning, nineteenth century poet" , "Butterfly" , "Boy's name" , "Founder of London's police force" .)