Usurp means to seize and hold illegally or by force.
Usurp is a verb.
Synonyms: appropriate, arrogate, grab, seize, illegally, snatch, steal, confiscate, commandeer.
Antonyms: give up, relinquish, yield, renounce, surrender.
The website is being sued for usurping copyrighted material.
Slowly the belligerent teenager began to usurp the authority of her parents.
The ruler's usurpation of the country caused enormous suffering.