These words are comparable in that they all mean to claim or take possession of something. To usurp is to seize and hold in possession such a thing as a position or status that belongs to another person and to which one has no legal right, and to exercise the authority and enjoy the privileges which stem from such a position. Usurp pertains especially to the forcible seizure of kingly power: an upstart pretender trying to usurp the throne.

Appropriate , as here considered, denotes the lawful or unlawful acquisition for one’s owe use of something originally belonging to another or to no one in particular. Thus, a farmer may legitimately appropriate water for irrigation from streams running through his farm; if unscrupulous, he may also appropriate parts of his neighbours?land.

Arrogate means to claim, demand or take that which belongs to another. It differs from the other words in this group in one particular way, that is, in its suggestion of he overbearing or haughty manner which accompanies arrogating: a university vice-chancellor who arrogated the right of deciding how each professor should conduct his examinations.

Confiscate means to appropriate by authority something that belongs to another, but not necessarily for one’s own use: Customs officials have the right to confiscate goods being smuggled into their country.

Originally pre-empt referred to the securing of the right of purchase of public land by occupying it and possibly improving it to substantiate the claim: They fenced the land to pre-empt it against other claimants. In general usage, pre-empt means to establish a prior claim to something which is sought by others: arriving early at the theatre so as to pre-empt the best seats.