Definition of "keel over" [keel• o•ver]

• Of a vessel: to roll so far on its side that it cannot recover; to capsize. (verb)
• To collapse in a faint; to black out; to die. (verb)

Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License

• "Several looked like they were ready to keel over and perform an Olympic face-plant."
• ""Dearest," he said, "don't slip that on your finger; put your arms around my neck and promise me, all at once and abruptly, or I'll keel over and die of sheer joy.""
• "Reverend Teaks would lay his hands on someone in the crowd to heal them and they would keel over with a heart attack instead."