What does “bomber” mean in rock climbing?

You’re climbing a multi-pitch route with your buddy. He’s belaying you on the fourth pitch, which is hard and scary. You’re worried about falling, but your partner calls up to you, “Dude, don’t worry about it! This belay is bomber!”

You’re not sure what this means, so you’re not sure whether to feel relieved or horrified.

In climbing, the words “bomber” and its cousin “bombproof” just mean super solid, usually in the context of pieces of gear (“This cam is bomber!”), rock quality (“The rock over here is bomber!”), and holds or grips (“The climb has bomber hand jams!”).

Bomber is the opposite of sketchy.