the act of usurping; esp., the unlawful or violent seizure of a throne, power, etc.
Origin:
ME usurpacion < L usurpatio
See usurpation in American Heritage Dictionary 4
noun
The act of usurping, especially the wrongful seizure of royal sovereignty.
A wrongful seizure or exercise of authority or privilege belonging to another; an encroachment: “in our own day, gross usurpations upon the liberty of private life”(John Stuart Mill).