( formal ) to be familiar / not familiar with sth because you have / have not experienced it many times before :
He is no stranger to controversy.
( formal ) to be familiar / not familiar with sth because you have / have not experienced it many times before :
He is no stranger to controversy.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005