Learn how to say Irredentist correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word irredentist:
a person who favours the acquisition of territory that once was part of his country or is considered to have been
of, relating to, or advocating this belief
C19: from Italian irredentista, from the phrase Italia irredenta, literally: Italy unredeemed, from ir-in-1 + redento redeemed, from Latin redemptus bought back; see redeem