Tailored suit, dull coats for musician (8)
I believe the answer is:
flautist
'for musician' is the definition.
(flautist is a kind of musician)
'tailored suit dull coats' is the wordplay.
'tailored' indicates an anagram (the letters are customised ).
'dull' becomes 'flat' (similar in meaning).
'coats' means one lot of letters goes inside another (inserted letters are coated in another word).
'suit' with letters rearranged gives 'utis'.
'utis' going within 'flat' is 'FLAUTIST'.
(Other definitions for flautist that I've seen before include "Studio recording period" , "Player of the flute" , "James Galway, say" , "James Galway, for example" , "Player of wind instrument" .)