( BrE , slang ) used to say, in a way that is not very polite, that you do not care about sth, or are not at all interested in it
I DON'T / COULDN'T GIVE A MONKEY'S
Meaning of I DON'T / COULDN'T GIVE A MONKEY'S in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005