Musician in suit, flat unfortunately (8)
I believe the answer is:
flautist
'musician' is the definition.
(flautist is a kind of musician)
'suit flat unfortunately' is the wordplay.
'unfortunately' is an anagram indicator.
'suit'+'flat'='suitflat'
'suitflat' with letters rearranged gives 'FLAUTIST'.
'in' acts as a link.
(Other definitions for flautist that I've seen before include "Musician" , "James Galway, for example" , "James Galway, say" , "Studio recording period" , "Player of wind instrument" .)