Prussia's ___ von Bismarck (4)
I believe the answer is:
otto
'prussia's von bismarck' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for otto that I've seen before include "Producer of engines" , "Italian for eight" , "perfume maker" , "Palindromic fragrance" , "Rose oil; man's name" .)