The Collaborative International Dictionary of English v.0.48:
Usurp \U*surp"\, v. t. [imp. & p. p. Usurped; p. pr. & vb. n.
Usurping.] [L. usurpare, usurpatum, to make use of, enjoy,
get possession of, usurp; the first part of usurpare is akin
to usus use (see Use, n.): cf. F. usurper.]
To seize, and hold in possession, by force, or without right;
as, to usurp a throne; to usurp the prerogatives of the
crown; to usurp power; to usurp the right of a patron is to
oust or dispossess him.
Alack, thou dost usurp authority. --Shak.
Another revolution, to get rid of this illegitimate and
usurped government, would of course be perfectly
Note: Usurp is applied to seizure and use of office,
functions, powers, rights, etc.; it is not applied to
common dispossession of private property.
Syn: To arrogate; assume; appropriate.