Word Study
usurper
CIDE DICTIONARY
usurper, n.
One who usurps; especially, one who seizes illegally on sovereign power; as, the usurper of a throne, of power, or of the rights of a patron. [1913 Webster]
"A crown will not want pretenders to claim it, not usurpers, if their power serves them, to possess it." [1913 Webster]
THESAURUS
usurper
Simon Legree, absolute monarch, absolute ruler, all-powerful ruler, arrogator, autarch, autocrat, caesar, commissar, czar, despot, dictator, disciplinarian, driver, duce, hard master, martinet, oligarch, oppressor, pharaoh, pretender, slave driver, stickler, tyrant, warlordROGET THESAURUS
usurper
Undueness
N undueness, malum prohibitum, impropriety, illegality, falseness, emptiness of title, invalidity of title, illegitimacy, loss of right, disfranchisement, forfeiture, usurpation, tort, violation, breach, encroachment, presumption, assumption, seizure, stretch, exaction, imposition, lion's share, usurper, pretender, undue, unlawful, unconstitutional, illicit, unauthorized, unwarranted, disallowed, unallowed, unsanctioned, unjustified, unentitled, disentitled, unqualified, disqualified, unprivileged, unchartered, illegitimate, bastard, spurious, supposititious, false, usurped, tortious, undeserved, unmerited, unearned, unfulfilled, forfeited, disfranchised, improper, unmeet, unfit, unbefitting, unseemly, unbecoming, misbecoming, seemless, contra bonos mores, not the thing, out of the question, not to be thought of, preposterous, pretentious, would-be, filius nullius.For further exploring for "usurper" in Webster Dictionary Online