Nickname for a physician (3)
I believe the answer is:
doc
'nickname for a physician' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for doc that I've seen before include "GP (informal)" , "Disney dwarf" , "Holliday (in 17 24)" , "GP (colloq.)" , "Fox perhaps" .)