A more thorough explanation:

A beggar-thy-neighbor policy is when a government takes actions to protect its own economy by making it harder for other countries to sell their goods in that country. This is usually done by raising tariffs (taxes on imports) or creating other barriers to trade. The goal is to increase domestic output and reduce unemployment, but it can harm other countries and lead to a trade war.

One example of a beggar-thy-neighbor policy is when a country raises tariffs on imported steel to protect its own steel industry. This makes it harder for other countries to sell their steel in that country, which can hurt those countries' economies and lead to retaliation.

Another example is when a country devalues its currency to make its exports cheaper and more competitive. This can make it harder for other countries to sell their goods in that country, and can lead to a race to the bottom as other countries also devalue their currencies.

These examples illustrate how a beggar-thy-neighbor policy can harm other countries and lead to a trade war. While it may benefit the country implementing the policy in the short term, it can ultimately hurt the global economy and lead to a lose-lose situation for everyone involved.