( informal ) used to emphasize that you do not know sth and that it is not important to you :
She could be dead for all I know.
( informal ) used to emphasize that you do not know sth and that it is not important to you :
She could be dead for all I know.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005