Which best describes a “narcotic” according to federal definitions?

The term "narcotic," as defined under federal law, refers specifically to a category of controlled substances that have the ability to dull the senses and alleviate pain. This definition aligns with the pharmacological properties of opioids, which are commonly classified as narcotics due to their significant pain-relieving effects and potential for abuse.

In the medical context, narcotics are often used to manage acute and chronic pain but also come with risks, including dependence and addiction. The federal definitions emphasize their role as controlled substances, meaning they are regulated due to their potential for misuse.

The other options describe substances that do not fit the definition of a narcotic. Over-the-counter pain relievers, while they may relieve pain, are not classified as narcotics. Non-controlled medications for anxiety and mood-enhancing supplements also do not possess the similar effects associated with narcotics, which is primarily focused on pain relief and sensory dulling. Thus, the correct choice reflects the characteristics outlined in federal law regarding narcotics.