To grant denizen status to a foreigner; to legally establish someone as a recognized resident or make them a denizen.
From denizen + -ize (suffix meaning 'to make or cause to become'). This is a back-formation from denizen, creating a verb from the noun.
Back-formations are when we take a noun like 'denizen' and invent a verb from it—we do this all the time in modern English (like creating 'google' from the noun Google).
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