[kongk, kawngk] 
| 1. | to break or fail, as a machine or engine (often fol. by out): The engine conked out halfway there. |
| 2. | to slow down or stop; lose energy (often fol. by out). |
| 3. | to go to sleep (usually fol. by off or out). |
| 4. | to lose consciousness; faint (usually fol. by out). |
| 5. | to die (usually fol. by out). |
conk out
Stop functioning, fail, as in The engine finally conked out. [Colloquial; early 1900s]
Fall asleep, as in Every evening he conked out in front of the television set. [1940s]
Faint or collapse, as in I don't know if it was the heat, but she suddenly conked out. [1920s]
Die, as in He's paranoid about conking out and he's only twenty! [Late 1920s]