Drastic extra power for Queen in court (9)
I believe the answer is:
desperate
'drastic' is the definition.
(thesaurus)
'extra power for queen in court' is the wordplay.
'extra power' becomes 'esp' (abbreviation for extrasensory perception).
'for' is a charade indicator (letters next to each other).
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'in' indicates putting letters inside.
'court' becomes 'date' (romantically pursue).
'esp'+'er'='esper'
'esper' put into 'date' is 'DESPERATE'.
(Other definitions for desperate that I've seen before include "Hopeless; extremely bad" , "Reckless" , "Eater sped to beyond hope" , "Adept seer (anag)" , "in a stew" .)