Feminine side (3)
I believe the answer is:
yin
'feminine side' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for yin that I've seen before include "principle accepted in China" , "Principle of cold and dark" , "Chinese female passive principle of universe" , "Complement of yang" , "Comedian Billy Connolly is the big one" .)