The Bank of England's anti-inflation efforts will come to nought if the U.S. Federal Reserve refuse to join in the plan.
The Bank of England's anti-inflation efforts will come to nothing if the U.S. Federal Reserve refuse to join in the plan.
Meaning of join in for the defined word.
Grammatically, this idiom "join in" is a phrase, more specifically, a phrasal verb. It's also a verb, more specifically, a phrasal verb and an intransitive verb.