Ivan was a terrible one (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
tsar
'ivan' is the definition.
(I've seen this in another clue)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for tsar that I've seen before include "Male monarch" , "Powerful man" , "Autocrat" , "Peter the Great, for example" , "Eg, Ivan the Terrible" .)