Definition of "let alone" []

• Much less; to say nothing of; used after one negative clause to introduce another, usually broader and more important clause, whose negation is implied by the negation of the first. (conjunction)
• Not to mention, as well as; used after one item, to introduce a further item which is entailed by the first. (conjunction)
• To leave alone, let be; to stop bothering. (verb)

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• "Not until after the fall of the Soviet Union in August 1991 did participants in the Soviet Moon program even admit their program existed, let alone that the N-1 disaster had occurred."
• "It was a tiny, ratty-looking house, scarcely big enough for the rats, let alone Frick."
• "I see the irony, but also wonder what happened to the Soviet couple after asking for prophylactics, let alone for political asylum."