Concerning a new specialist (5)
I believe the answer is:
anent
'concerning' is the definition.
(I've seen this in another clue)
'a new specialist' is the wordplay.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'specialist' becomes 'ent' (Ear, Nose and Throat specialist).
'a'+'n'+'ent'='ANENT'
(Other definitions for anent that I've seen before include "About (Scottish)" , "Concerned with" , "Concerning (archaic)" .)