Sister hiding in kitchen unit (3)
I believe the answer is:
nun
'sister' is the definition.
(thesaurus)
'hiding in kitchen unit' is the wordplay.
'hiding' says the answer is hidden in the clue.
'NUN' is hidden in the letters of 'in kitchen unit'.
(Other definitions for nun that I've seen before include "Woman in Holy Orders" , "Mother Teresa, maybe" , "eg Carmelite" , "Woman in religious order" , "She's made vows" .)