Queen able, not needing equerry initially (4)
I believe the answer is:
anne
'queen' is the definition.
(I've seen this before)
'able not needing equerry initially' is the wordplay.
'initially' indicates taking the first letters.
The first letters of 'able not needing equerry' is 'ANNE'.
(Other definitions for anne that I've seen before include "Girl's name" , "First queen of Great Britain and Ireland" , "Last Stuart monarch, d. 1714" , "--- Elliot, later Wentworth (J. Austen)" , "The Princess Royal" .)