One who expropriates; a person or authority that seizes or takes away property, usually a government or governmental agent.
From 'expropriate' plus the suffix '-or' meaning 'one who does.' The expropriator is the active agent performing the seizure.
An expropriator—usually a government entity—has enormous power over individual lives, which is why constitutional law in democracies carefully limits when and how expropriatiors can act, and requires them to pay fair compensation.
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