Physician upset in racket harmful to health (7)
I believe the answer is:
noisome
'harmful to health' is the definition.
(I've seen this before)
'physician upset in racket' is the wordplay.
'physician' becomes 'mo' (abbreviation for medical officer).
'upset' shows that the letters should be reversed in order.
'in' indicates putting letters inside.
'racket' becomes 'noise' (racket can mean a loud noise).
'mo' backwards is 'om'.
'om' inserted inside 'noise' is 'NOISOME'.
(Other definitions for noisome that I've seen before include "Smelling badly" , "Harmful - offensive" , "Offensive, noxious" , "Odorous" , "Repellent" .)