Doctor reveals a few (7)
I believe the answer is:
several
'a few' is the definition.
(I've seen this in another clue)
'doctor reveals' is the wordplay.
'doctor' indicates anagramming the letters.
'reveals' anagrammed gives 'SEVERAL'.
(Other definitions for several that I've seen before include "three or four" , "quite a lot" , "More than one or two" , "A few; separate" , "Divers" .)