One who preempts; especially, one who appropriates public land.(noun)
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Use "preemptor" in a sentence
"KING: Is the jail that he's in now any kind of a preemptor for it?"
"GRACE: No. KING: The question was, what is it like to be the preemptor of sending someone to the death penalty?"
"He knew the man, a preemptor of Folly Bay, a truckler to the cannery because he was always in debt to the cannery, -- and a quarrelsome individual besides, who took advantage of his size and strength to browbeat less able men."