"Young Frankenstein" assistant (4)
I believe the answer is:
igor
'young frankenstein assistant' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for igor that I've seen before include "Card game" , "Stravinsky's first name" , "Prince in Borodin's opera" , "Prince of Russian opera" , "Maybe 8 [SIKORSKY]" .)