Terrible title for tsar (4)
I believe the answer is:
ivan
'for tsar' is the definition.
(name of several Russian tsars)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ivan that I've seen before include "his progress in history was terrible!" , "- - the Terrible (Czar)" , "man who had a terrible reputation" , "Vain (anag) - Tsar of Russia" , "A Terrible old Russian ruler" .)