Pronunciation: (yOO-sûrp', -zûrp'),[key] —v.t. 1. to seize and hold (a position, office, power, etc.) by force or without legal right: The pretender tried to usurp the throne. 2. to use without authority or right; employ wrongfully: The magazine usurped copyrighted material.
—v.i. to commit forcible or illegal seizure of an office, power, etc.; encroach.