A more thorough explanation:

Subjugation is a term used in international law to describe the process of ending a war and acquiring territory when one of the countries involved in the war has been so completely defeated that the other country can decide what happens to the defeated country's territory. This process is also known as debellatio.

For example, if Country A and Country B are at war and Country A is completely defeated by Country B, Country B can decide what happens to Country A's territory. This could mean annexing the territory or establishing a new state in the occupied territory.

The concept of subjugation or debellatio is controversial because it raises questions about the legality and morality of acquiring territory through conquest. Some argue that it is a violation of international law and the principles of self-determination and sovereignty.