Sycophant is more prostrate before Queen (9)
I believe the answer is:
flatterer
'sycophant' is the definition.
(thesaurus)
'more prostrate before queen' is the wordplay.
'more prostrate' becomes 'flatter' ('flat' can be a synonym of 'prostrate').
'before' is a charade indicator (letters next to each other).
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'flatter'+'er'='FLATTERER'
'is' is the link.
(Other definitions for flatterer that I've seen before include "Sycophant" , "One uses butter" , "Person who imitates, perhaps" .)