世故 (shì gu): the ways of the world

Having struggled in society for so many years, he became very worldly and can chat easily with anyone.

Although she is young, she speaks and acts very worldly, and her colleagues all admire her.

He is too worldly; when trouble arises, he always considers his own interests first and never allows himself to be at a disadvantage.

Young people should keep some sincerity and not become worldly too early, otherwise they will lose many friends.