A person who transfers or assigns property, rights, or contractual obligations to another person (the assignee).
From 'assign' plus the agent suffix '-or' (one who performs an action), ultimately from Latin 'assignare' (to allot). The '-or' variant became standard in formal legal language.
In contract law, the 'assignor' is trying to dump obligations onto someone else, which is why so many contracts specifically forbid assignment—they want to keep you responsible, not some random 'assignee' you picked.
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