Nonfiction movie, for short (3)
I believe the answer is:
doc
'nonfiction movie for short' 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 "Medic, in short" , "Holliday (in 17 24)" , "GP (colloq.)" , "Medic (familiar)" , "scaled-down version of GP" .)