Mercury, say, is a scorcher? (6)
I believe the answer is:
singer
'mercury say' is the definition.
(I know this)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for singer that I've seen before include "Crooner" , "Song performer" , "Vocalist" , "Make of sewing machine" , "Performer of songs" .)