Queen follows favourite saint (5)
I believe the answer is:
peter
'saint' is the definition.
(St Peter)
'queen follows favourite' is the wordplay.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'follows' says to put letters next to each other.
'favourite' becomes 'pet' (synonyms).
'er' after 'pet' is 'PETER'.
(Other definitions for peter that I've seen before include "Leading apostle" , "prison cell" , "and 14 dn Latest actor to play Doctor Who" , "- Grimes (Britten)" , "Saint at the Pearly Gates?" .)