Presumption: that which may be logically assumed to be true until disproved; an assumption. In law, a fact assumed because of the proof of other facts; in patent law, for example, a patent enjoys a “presumption of validity” because it was issued by the U.S. Patent and Trademark Office; in a lawsuit for patent infringement, however, the alleged infringer will seek to show that the patent is not valid, for a variety of reasons.
Presumptuous: impertinent, unjustifiably bold, excessively forward.
Note: The adjective presumptive means having a reasonable basis for acceptance or belief, as in the presumptive candidate for president.
You may consider me presumptuous, gentlemen, but I claim to be a citizen of the United States, with all the qualifications of a voter. I can read the Constitution, I am possessed of two hundred and fifty dollars, and the last time I looked in the old family Bible I found I was over twenty-one years of age.
—Elizabeth Cady Stanton Quoted in History of Woman Suffrage (1881)