irredentist
A person who advocates for the recovery of territory considered historically or ethnically part of their nation. Used in political and historical contexts.
As an irredentist, he strongly demands the return of lost territories.
The ideology of irredentism, while 領土回復主義者 refers to a person who holds that ideology.
Compound of 領土 (territory), 回復 (recovery), 主義 (doctrine), and 者 (person). The term is a direct translation of the Western political concept of irredentism.