Grand pubs prepared to welcome monarch (6)
I believe the answer is:
superb
'grand' is the definition.
(thesaurus)
'pubs prepared to welcome monarch' is the wordplay.
'prepared' indicates an anagram.
'to welcome' is an insertion indicator (in sense of 'inviting in').
'monarch' becomes 'er' (abbreviation for Elizabeth Regina).
'pubs' with letters rearranged gives 'supb'.
'supb' going around 'er' is 'SUPERB'.
(Other definitions for superb that I've seen before include "Gorgeous" , "Tiptop" , "Magnificent, quite splendid" , "Quite splendid, really excellent" , "Of surpassing excellence" .)