Wallachian ruler restructured DVLA (4)
I believe the answer is:
vlad
'wallachian ruler' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'restructured dvla' is the wordplay.
'restructured' indicates an anagram (I've seen 'restructuring' mean this).
'dvla' with letters rearranged gives 'VLAD'.
Can you help me to learn more?
(Other definitions for vlad that I've seen before include "Infamous impaler" , "__ Dracula, the 15th century Prince of Wallachia, called the Impaler" .)