Excess praise one's Queen rejected (8)
I believe the answer is:
residual
'excess' is the definition.
(thesaurus)
'praise one's queen rejected' is the wordplay.
'praise' becomes 'laud' (lauding is a kind of praising**).
'one's' becomes 'is' (roman numeral).
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'rejected' says the letters should be written in reverse.
'laud'+'is'+'er'='laudiser'
'laudiser' reversed gives 'RESIDUAL'.
(Other definitions for residual that I've seen before include "Remaining; repeat royalty" , "Remaining at the end" , "Leftover - used rail (anag)" , "surplus" , "Left over as a remainder" .)