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

My brother has decided to settle in London for good.

forever

The most appropriate meaning of the underlined idiom "for good" in the sentence "My brother has decided to settle in London for good" is forever.

The other options are incorrect.

• "Briefly" means for a short period of time, while for good means forever.
• "For a better income" means to move to a place with a higher standard of living, while for good means to move to a place with the intention of staying there permanently.
• "For a promotion" means to move to a new job with a higher position, while for good means to move to a new place with the intention of staying there permanently.

The idiom "for good" is used to mean forever or permanently. So, when someone says that they are going to do something for good, it means that they are going to do it forever or permanently. In the sentence "My brother has decided to settle in London for good", it means that the brother is going to live in London forever.