See leave someone alone.
Not to mention, as in We have no room for another house guest, let alone an entire family. [c. 1800]
Words nearby let alone
How to use let alone in a sentence
Genetics alone does not an eating disorder make, generally speaking, and Bulik points out that environment still plays a role.How Skinny Is Too Skinny? Israel Bans ‘Underweight’ Models|Carrie Arnold|January 8, 2015|DAILY BEAST
I watch every episode alone on my couch and I just sit there and laugh, and laugh.Coffee Talk with Fred Armisen: On ‘Portlandia,’ Meeting Obama, and Taylor Swift’s Greatness|Marlow Stern|January 7, 2015|DAILY BEAST
By contrast, John McCain, the eventual GOP nominee, had raised approximately $12.7 million in the first quarter of 2007 alone.
Nor should we ever assume that weather alone, however extreme, should be fatal to a commercial flight.
Women and children are disproportionately victims, but they are not alone.ISIS, Boko Haram, and the Growing Role of Human Trafficking in 21st Century Terrorism|Louise I. Shelley|December 26, 2014|DAILY BEAST
Ten minutes later, veiled and cloaked, she stepped out alone into the garden.Hilda Lessways|Arnold Bennett
The two women had no intention of bathing; they had just strolled down to the beach for a walk and to be alone and near the water.The Awakening and Selected Short Stories|Kate Chopin
When we were mounted Mac leaned over and muttered an admonitory word for Piegan's ear alone.
If Mac had been alone he would have made the post by sundown, for the Mounted Police rode picked horses, the best money could buy.
Alone Orlean lay trying vainly to forget something—something that stood like a spectre before her eyes.The Homesteader|Oscar Micheaux