usurp /yu̇-'sərp, -'zərp/ vb [Latin usurpare to take possession of without a strict legal claim, from usus use + rapere to seize]vt: to seize and hold (as office, place, or powers) in possession by force or without rightthe courts may not usurp the powers of the legislaturevi: to seize or exercise authority or possession wrongfullyusur·pa·tion /ˌyü-sər-'pā-shən, -zər-/ nusurp·er /yu̇-'sər-pər, -'zər-/ n
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.
accroach, appropriate unlawfully, arrogate, assume, assume command, assume without authority, commandeer, encroach, help oneself to, hold by force, lay hold of, seize, seize power, sibi adsumere, squat, steal, take, take charge, take possession, wrest
abridge (divest), accroach, adopt, annex (arrogate), assume (seize), attach (seize), condemn (seize), depose (remove), deprive, dislodge, impropriate, infringe, invade, levy, overstep, preempt, seize (confiscate), steal, supplant, takeover, trespass
Burton's Legal Thesaurus. William C. Burton. 2006
v.To take over; to supplant; to take over a position of power by force.n.usurpation
The Essential Law Dictionary. — Sphinx Publishing, An imprint of Sourcebooks, Inc. Amy Hackney Blackwell. 2008.