A fabulous rose given to the Queen (9)
I believe the answer is:
sovereign
'the queen' is the definition.
(thesaurus)
'a fabulous rose given' is the wordplay.
'a fabulous' indicates an anagram.
'rose'+'given'='rosegiven'
'rosegiven' anagrammed gives 'SOVEREIGN'.
'to' is the link.
(Other definitions for sovereign that I've seen before include "Outstanding" , "Ruler - gold coin" , "Head of state" , "Her Maj?" , "Supreme ruler" .)