yin 
/ˈjɪn/ noun
/ˈjɪn/ noun [noncount] in Chinese philosophy : one of the two forces that together form everything that exists : the female principle of the universe that is considered dark and passive and is associated with earth — compare yang
the yin and yang
chiefly US : the two opposite sides or parts of something
▪ learning about the yin and yang of politics
▪ learning about the yin and yang of politics
