• (RP) IPA: /ˈkiːl ˈəʊvə(ɹ)/
• (GA) IPA: /ˈkil ˈoʊvɚ/

keel over

1. (intransitive, nautical, also figuratively) Of a vessel: to roll#Verb|roll so far on its side#Noun|side that it cannot recover; to capsize or turn turtle.
   • 1851 November 13, Herman Melville, “The Town-Ho’s Story. (As Told at the Golden Inn.)”, in Moby-Dick; or, The Whale, 1st American edition, New York, N.Y.: Harper & Brothers; London: Richard Bentley, OCLC 57395299 ↗, page 289 ↗:

     [H]is bandaged cry was, to beach him on the whale's topmost back. Nothing loath, his bowsman hauled him up and up, through a blinding foam that blent two whitenesses together; till of a sudden the boat struck as against a sunken ledge, and keeling over, spilled out the standing mate.

2. (intransitive, idiomatic) To collapse#Verb|collapse in a faint#Noun|faint; to black out, to swoon#Verb|swoon.

   We should all go inside before somebody keels over from the heat.

   • 1876, Mark Twain [pseudonym; Samuel Langhorne Clemens], chapter XVI, in The Adventures of Tom Sawyer, Hartford, Conn.: The American Publishing Company, OCLC 1000326417 ↗, page 138 ↗:

     "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!"

3. (intransitive, idiomatic) To die#Verb|die.

• French: se retourner, se renverser, chavirer
• German: kentern
• Russian: переверну́ться
• Spanish: zozobrar, volcar

• French: tomber dans les pommes
• Russian: отключи́ться