When a state seeks to acquire the neighboring territoy that is home to ethnically similar people and territory on the other side of its international border by appealing to a concentrated group?

This can be described as irredentism, where a state seeks to reclaim or annex territory that it considers to be part of its historical homeland or that is home to ethnically similar people. The state may appeal to the target population in the neighboring territory to support its claims, citing shared cultural ties or historical connections. This can lead to tensions between countries and potential conflicts over territorial claims.