Select the most appropriate meaning of the underlined idiom in the given sentence.

A fair-weather friend can never be trusted in the times of exigency.

A selfish friend

The most appropriate meaning of the underlined idiom "fair-weather friend" in the given sentence is a selfish friend.

A fair-weather friend is someone who is only a friend when things are going well. They are not there for you when you need them most.

In the given sentence, the speaker is saying that a fair-weather friend can never be trusted in times of need. This means that a fair-weather friend will not be there for you when you are going through a difficult time.

The other options are incorrect:

• A close friend: A close friend is someone who is always there for you, even when things are tough.
• A pen friend: A pen friend is someone you write to, but you may never have met them in person.
• An old acquaintance: An old acquaintance is someone you know, but you are not close to them.