Haze follows revolutionary scientist (7)
I believe the answer is:
chemist
'scientist' is the definition.
(chemist is a kind of scientist)
'haze follows revolutionary' is the wordplay.
'haze' becomes 'mist' (I've seen this before).
'follows' is a charade indicator (letters next to each other).
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'mist' put after 'che' is 'CHEMIST'.
(Other definitions for chemist that I've seen before include "Drugstore" , "Drug dispenser" , "Shop selling medicines" , "Nobel, say" , "Shop for drugs" .)