Going Out On a Limb
A person can be “disarmed” without amputation because “arms” in this context is short for “armaments,” or the weapons of warfare.
The association of “bootleg” meaning homemade, smuggled, or somehow unauthorized was boosted by the booming illegal alcohol trade of the Prohibition era, but the term actually started in the previous century to describe smuggling flasks inside the legs of high boots in states which had already banned booze.
To undercut or sabotage yourself is sometimes called “shooting yourself in the foot,” after the common WWI practice of soldiers doing so to avoid being sent into battle on account of their “accidental” injury.
You’ve heard of “the long arm of the law,” but in the US, many states formalize this in “long arm statutes.” These laws give state courts jurisdiction over out-of-state businesses through some connection with the long-armed state, such as selling products or employing people there.
Easy, undisputed victory is called “hands down” because horse jockeys who felt sure to win would lower or even drop their reins and relax as they crossed the finish line, according to 19th century racing journalists who coined the term.
Don’t get caught “flat-footed,” or unprepared. In action stance parlance, this is the opposite of being “on your toes,” or ready, at least in the baseball world where it got the unready connotation. A century before, however, it was a firm and resolute person who stood “flat-footed.”
You’ve “got a leg up” on the competition if you have some advantage or extra assistance on your side. Another horse-based idiom, this referred to the help a rider would get from an assistant in mounting a horse.