What term characterizes someone who is audacious and often rude?

The term that describes someone who is audacious and often rude is "brazen." This word conveys a sense of boldness that crosses the line into discourteous or disrespectful behavior. Individuals characterized by this term tend to act with an impudent confidence, often disregarding social norms or the feelings of others.

In contrast, the other terms do not encapsulate the same meaning. "Belligerent" generally refers to someone who is aggressive or combative, which emphasizes hostility rather than audacity or rudeness. "Candid" describes someone who is frank and honest, highlighting transparency rather than audacious behavior. "Callous" pertains to a lack of empathy or insensitivity, which can imply a certain rudeness, but does not specifically capture the boldness or audacity that "brazen" emphasizes. Thus, "brazen" is the most fitting term for someone who is both audacious and often rude.