Indestructible, being constructed of such materials and in such a way that much abusive handling cannot cause considerable damage, if at all.
Dude, your car just drove over a landmine and you survived! That thing's bombproof!!!!!
In rock climbing, an anchor (or series of anchors) that is so sturdy, it is essentially impossible for it to fail.
Make sure your anchors are bombproof, dude, otherwise you'll probably die, because you're a crappy climber. And you're a bad person, too, so you'd probably burn in hell for all time.