The opening of your digestive tract. It's Latin for "ring" or "circle". You know that muscle that contracts when you have to do number two? That's your anus. Also comically referred to as the distant planet "uranus".
A tough guy or dangerous man. This goes back to the days of Gunsmoke, hayseeds, John Waynes and wild west saloons. Back when curly wolves were "reckoned with" instead of shot at by some punk with mommy and daddy issues.