To guard means to watch over and protect something or someone from harm or danger. A museum guard protects valuable paintings from thieves. A bodyguard keeps an important person safe. Your dog might guard your house by barking when strangers approach. When you guard your lunch money carefully, you keep it in a safe pocket so you won't lose it.

In basketball, guards are players who handle the ball and defend against the other team's offense. They got this name because their original job was to guard their team's basket from the opposing players. Point guards and shooting guards each have different roles, but both play near the perimeter of the court.

The word also means being careful or cautious about something. When you guard your words, you think before speaking to avoid saying something hurtful. A poker player guards her expressions so opponents can't tell if she has good cards. Being on guard means staying alert and ready, like a soldier watching for danger or a student prepared for a surprise quiz.

Someone who is guarded in conversation doesn't reveal much about themselves. They protect their private thoughts and feelings, sharing only what feels safe. This isn't necessarily bad: being appropriately guarded with strangers can show good judgment, though being too guarded with friends can make real connection difficult.