Musician roasting furiously (8)
I believe the answer is:
organist
'musician' is the definition.
(I know that organist is a type of musician)
'roasting furiously' is the wordplay.
'furiously' is an anagram indicator (the letters move around energetically or furiously).
'roasting' anagrammed gives 'ORGANIST'.
(Other definitions for organist that I've seen before include "One plays in church usually" , "Church instr. player" , "Accompanist, keyboard player" , "It groans for church musician" , "Cathedral musician" .)