One roped in emperor (4)
I believe the answer is:
nero
'emperor' is the definition.
(Roman emperor)
'one roped in' is the wordplay.
'in' says the answer is hidden in the clue.
'NERO' can be found hidden inside 'one roped'.
(Other definitions for nero that I've seen before include "Emperor said to have started the fire that destroyed Rome" , "Roman emperor who fiddled while Rome burned" , "Emperor (who fiddled while Rome burned?) d. AD68" , "Roman tyrant" , "Roman emperor on the fiddle?" .)