bombproof
adj.— «Riders are dressed casually in jeans, workout wear and riding helmets. They’re on horses referred to as “bombproof”—they’re unlikely to injure a rider.» —“Hockey on horseback: St. Louis club introduces polo for the masses” in Defiance, Missouri Canadian Press Aug. 10, 2008. (source: Double-Tongued Dictionary)
Further reading
You might be surprised to learn that a “hoosier” isn’t necessarily from Indiana. Around the St. Louis, Missouri, area, the term hoosier has a whole other meaning. And: Scotland is the home of the Golden Spurtle world championship, but what exactly...
Mary-Clare recalls that when she was growing up in St. Louis, Missouri, everyone she knew used the term hoosier as a kind of teasing pejorative. If someone did something silly, others would say You’re such a hoosier, the adjective hoozh, or jokingly...