Select the most appropriate meaning of the given idiom.

On the ball

To be alert

The most appropriate meaning of the given idiom "on the ball" is to be alert.

This idiom means to be aware of what is happening and to be ready to act quickly. It is often used to describe someone who is performing well at their job or who is able to handle a difficult situation effectively.

The other options are incorrect:

• Doing a bad job: This is not the meaning of the idiom "on the ball."
• Doing an average job: This is not the meaning of the idiom "on the ball."
• To be lazy: This is not the meaning of the idiom "on the ball."