Select the most appropriate meaning of the given idiom.

When pigs fly

A time that will never come

The most appropriate meaning of the idiom "when pigs fly" is a time that will never come.

This idiom is used to express skepticism or disbelief about something that is very unlikely to happen. For example, someone might say "when pigs fly" if you tell them that you are going to win the lottery or that you are going to quit your job and travel the world.

The other options are not as accurate descriptions of the meaning of the idiom.

• A difficult situation: This is more accurately described by the idiom "a tough spot."
• An argument between two people: This is more accurately described by the idiom "a heated exchange."
• A practical idea: This is more accurately described by the idiom "a sound plan."