Select the most appropriate meaning of the given idiom.

Be glad to see the back of

Be happy when a person leaves

The most appropriate meaning of the idiom "be glad to see the back of" is be happy when a person leaves.

The other options are incorrect.

• Be happy at another's success does not mean be happy when a person leaves. Being happy at another's success means to be pleased that someone else has achieved something.
• Be relieved at another's failure does not mean be happy when a person leaves. Being relieved at another's failure means to be glad that someone else has not succeeded.
• Be happy to see someone again does not mean be happy when a person leaves. Being happy to see someone again means to be pleased to see someone after a period of time.

The idiom "be glad to see the back of" comes from the idea of being happy when someone leaves and you no longer have to see them. In the same way, to be glad to see the back of someone means to be happy when they leave and you no longer have to deal with them. For example, you might say that you were glad to see the back of your ex-partner after a difficult breakup.