Infamous emperor (4)
I believe the answer is:
nero
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">infamous emperor</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nero that I've seen before include "Roman Emperor, 54-68 AD" , "Roman emperor infamous for his cruelty" , "Emperor, 'burnt' Rome" , "Roman 9" , "He's reputed to have fiddled while Rome burned" .)