c (idiomatic|negative polarity item)much less | Much less; to say nothing of; (non-gloss definition|used after one negative clause to introduce another, usually broader and more important clause, whose negation is implied by the negation of the first.)
c (idiomatic|positive polarity item|rare)not to mention, as well as; (non-gloss definition|used after one item, to introduce a further item which is entailed by the first.)