Hitler's expansionist policies were a set of aggressive strategies aimed at acquiring territory for Germany, driven by the belief in the need for 'Lebensraum' or living space for the Aryan race. These policies were rooted in nationalist and militaristic ideologies that sought to expand German borders, primarily targeting Eastern Europe, and played a critical role in the lead-up to World War II. The quest for territorial expansion directly influenced the implementation of oppressive measures, including the systematic extermination of millions during the Holocaust.