Select the most appropriate meaning of the given idiom.

Beside oneself

Almost out of one’s senses

The most appropriate meaning of the given idiom "Beside oneself" is (1) Almost out of one’s senses.

The other options do not fit the meaning of the idiom.

• In the secret means to know something that is not known to others.
• Under all conditions means in all circumstances.
• To stand for one’s own fault means to accept responsibility for one’s own mistakes.

The idiom "beside oneself" is used to describe someone who is so shocked, surprised, or angry that they are almost out of control. It is often used to describe someone who is behaving in a way that is not normal or rational.