Past tense of extermine; was completely destroyed or eliminated (archaic usage).
From extermine (archaic verb) + -ed (Old English past tense marker). This is the regular past tense of the older verb form.
If you read old texts and see 'extermined,' you're looking at Early Modern English—by the time of the Industrial Revolution, people had mostly shifted to 'exterminated.'
Complete word intelligence in one call. Free tier — 50 lookups/day.