Religious woman in non-union organisation (3)
I believe the answer is:
nun
'religious woman' is the definition.
(woman who has taken religious vows)
'in non-union organisation' is the wordplay.
'in' indicates a hidden word.
'NUN' is hidden within 'non union organisation'.
(Other definitions for nun that I've seen before include "Devout woman" , "Female in religious order" , "Convent dweller" , "Woman with a habit" , "religious person" .)