Emperor and Queen in negative response (4)
I believe the answer is:
nero
'emperor' is the definition.
(Roman emperor)
'queen in negative response' is the wordplay.
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'in' means one lot of letters goes inside another.
'negative response' becomes 'no' (I've seen this in other clues).
'er' put into 'no' is 'NERO'.
'and' is the link.
(Other definitions for nero that I've seen before include "Matricidal emperor" , "Wicked fiddler" , "Emperor who played the fiddle" , "He's reputed to have fiddled while Rome burned" , "Fiddling Roman emperor" .)