WordWeb Online

1. Take control of (without authority and possibly with force); take as one's right or possession
   "he usurped my rights";
   - assume, seize, take over, arrogate
    
2. Take the place of
   "gloom had usurped mirth at the party after the news of the terrorist act broke"

Derived forms: usurped, usurps, usurping

Type of: replace, supercede [non-standard], supersede, supervene upon, supplant, take

Encyclopedia: Usurp