A person who assigns or transfers property, rights, or responsibilities to another person.
From 'assign' plus the agent suffix '-er' (one who does the action). Contrasts with 'assignee,' the person receiving the assignment.
While 'assignor' is the standard legal term, 'assigner' appears in some older documents and shows how English legal language competed between '-er' and '-or' suffixes before standardizing on '-or' for most formal roles.
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