keel over

The original nautical meaning (sense 1) refers to a vessel rolling to the extent that its keel (“a large beam along the underside of the vessel’s hull from bow to stern”) is visible.

• "We should all go inside before somebody keels over from the heat."
• "A huge double-fisted fellow hits Marshall a biff on the ear; the General keels over and catches in his fall another gentleman, who hits a fourth, and the party clinging, all fall through a window, and drop through a partly closed cellar-door."
• ""I bleeve I could smoke this pipe all day," said Joe. "I don't feel sick." / "Neither do I," said Tom. "I could smoke it all day. But I bet you Jeff Thatcher couldn't." / "Jeff Thatcher! Why he'd keel over just with two draws. Just let him try it once. He'd see!""
• "The enemy had planted a piece of ordinance within gun-shot of the fort during the night, and the first thing in the morning they commenced a brisk cannonade, point-blank, against the spot where I was snoring. I turned out pretty smart, and mounted the rampart. The gun was charged again, a fellow stepped forth to touch her off, but before he could apply the match I let him have it, and he keeled over. A second stepped up, snatched the match from the hand of the dying man, but Thimblerig, who had followed me, handed me his rifle, and the next instant the Mexican was stretched on the earth beside the first."
• "A staunch old ship she was too, […] There was no hurry in her building. Mynheer Von Dert hewed the logs for her keel, and slept with his fathers. His son Petrus prepared the keelson, then keeled over, and was laid beside his venerable sire."
• "Plucky old Walder Frey gathers his family for a feast and toasts to their massacre of the Stark family. He compliments their bravery in stabbing a pregnant woman and her fetus to death. As every last Frey man swigs their special wine, Walder hypes the cunning it took to invite guests into your home and ambush them. But then things take a turn, the men starting to keel over as Walder seems to admonish them for leaving certain threads hanging. At last the room is empty but for Arya Stark, holding Walder Frey's face, and a couple girls she leaves alive to spread the legend. "Winter came for House Frey.""