Definition of Beggar My Neighbour Policy: This is an economic policy that seeks to promote a country’s economy at the expense of another country.
An obvious example, is the use of tariff barriers. A country may place tariff on imports to help promote local domestic industry. This may help local unemployment, but, be at the expense of the other country’s export sector.
Some economists argue that imposing tariff’s doesn’t help the domestic economy, but, only certain sectors of the economy.
Beggar my neighbour policy could also be used with regard to exchange rates. For example, the US criticise China for having a low exchange rate. They argue this increases Chinese growth at the expense of a US trade deficit.