Wiktionary
n. 1 a hypothetical weapon that has the capacity to destroy the Earth. 2 a bomb that is capable of causing widespread or total destruction.
Usage examples of "doomsday weapon".
The first was that he had been able to activate the doomsday weapon in the first place.
With Nadeen Selassie's doomsday weapon in the picture, we almost went yesterday, and we could all go tomorrow.
And I'd have this secret hideout, in an extinct volcano, with all these special trains that travel along secret tunnels and a Doomsday weapon and this white cat that sat on my knee and—.
We were still far from having rebuilt an advanced tech base, but we could produce guns and tanks and napalmand, of course, the Faithful built their doomsday weapon as a last resort.
He didn't look like a doomsday weapon anymore, or even like a vampire.
The Externalists, with characteristic tunnel vision, maintained that the disrupters were simply the final form of the Draan doomsday weapon that had started by causing the nothings and came to full cycle in the Final Cataclysm.