Stupidly, I resent Queen being a horsewoman (12)
I believe the answer is:
equestrienne
'a horsewoman' is the definition.
(I've seen this before)
'stupidly i resent queen' is the wordplay.
'stupidly' indicates an anagram.
'i'+'resent'+'queen'='iresentqueen'
'iresentqueen' with letters rearranged gives 'EQUESTRIENNE'.
'being' acts as a link.
(Other definitions for equestrienne that I've seen before include "For example, Godiva" , "Horsewoman" , "Female rider" .)