Английский словарь американских идиом - much less

{conj.} And also not; and even less able or likely to. - Used after a negative clause. * /I never even spoke to the man, much less insulted him./ * /John couldn't even pick up the box, much less carry it upstairs./ * /George can hardly understand arithmetic, much less algebra./ Compare: LET ALONE, NOT TO MENTION.