Wiktionary
n. (context military slang English) An instance of damage a vehicle by weaponry that renders it both unusable and unrepairable.
Wikipedia
A catastrophic kill, K-Kill or complete kill is damage inflicted on an armored vehicle that amounts to complete destruction of the vehicle, rendering it both permanently non-functional and unrepairable.
The term knocked out refers to a vehicle which has been damaged to the point of inoperability and abandoned by its crew, but is not obviously beyond the point of repair. While a knocked-out vehicle may be later determined to be irreparable and written off, a K-kill is more obvious and usually involves the destruction of the vehicle by fire and/or explosion. Among tank crewmen it is also commonly known as a brew up, coined from the British World War II term for lighting a fire in order to brew tea. The expression arose because British troops used an old petrol tin with holes punched in the side as a makeshift stove on which to brew their tea. The flames licking out of the holes in the side of the tin resembled a burning tank and thus the expression was coined.
Typically a catastrophic kill results in the ignition of any fuel the vehicle may be carrying as well as the detonation ( cooking off, or sympathetic detonation) of its ammunition. A catastrophic kill does not necessarily preclude the survival of the vehicle's crew, although most historical casualties in armored warfare were the result of K-kills.
This type of kill is also associated with the jack-in-the-box effect, where a tank's turret is blown skyward due to the overpressure of an ammunition explosion. Some tank designs employ blow-off panels, channeling such explosions outside of the vehicle, turning an otherwise catastrophic kill into a firepower kill.
Usage examples of "catastrophic kill".
The grenadiers were down to hand to hand and as he reached the line he saw the turret of one of the remaining Leopards leap into the air in a catastrophic kill.
That one had suffered a catastrophic kill and the turret was fifty feet to the side, buried halfway into the moutainside.
The detonation of the Lamprey's fuel source had not been as large as the first catastrophic kill, but it was still quite spectacular.