Take out bird wearing best (9)
I believe the answer is:
eliminate
'take out' is the definition.
(thesaurus)
'bird wearing best' is the wordplay.
'bird' becomes 'mina' (mina is a kind of bird**).
'wearing' indicates putting letters inside.
'best' becomes 'elite' (I've seen this before).
'mina' going within 'elite' is 'ELIMINATE'.
(Other definitions for eliminate that I've seen before include "defeat" , "Do away with, get rid of" , "waste" , "Knock out" , "Eradicate" .)