Hornet destroyed royal seat (6)
I believe the answer is:
throne
'royal seat' is the definition.
(I've seen this before)
'hornet destroyed' is the wordplay.
'destroyed' indicates anagramming the letters.
'hornet' anagrammed gives 'THRONE'.
(Other definitions for throne that I've seen before include "Seat of monarch" , "Seat of a ruler" , "Regal seat" , "Royal chair" , "Royalty sits on it" .)