1. To seize and hold (the power or rights of another, for example) by force or without legal authority.
2. To take over or occupy without right: usurp a neighbor's land.
3. To take the place of (another) without legal authority; supplant.
To seize another's place, authority, or possession wrongfully.
[Middle English usurpen, from Old French usurper, from Latin srpre, to take into use, usurp; see reup- in Indo-European roots.]
usurper | n.
usurpingly | adv.
usurped, usurping, usurps | v.
usurpative , usurpatory | adj.