Select the most appropriate meaning of the given idiom.

To hit below the belt

To fight unfairly

The most appropriate meaning of the idiom "to hit below the belt" is to fight unfairly.

The other options are not correct meanings of the idiom "to hit below the belt".

• A close fight is a fight that is evenly matched and could go either way.
• With full energy means to fight with all of one's strength and determination.
• To get into trouble means to do something that is wrong or illegal.