presumption

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Behavior or attitude that is boldly arrogant or offensive; effrontery.
• noun The act of presuming or accepting something as true.
• noun A condition or basis for accepting or presuming something.
• noun Law A conclusion applied by law as to the correctness of some fact, ordinarily subject to rebuttal by contrary evidence.

from The Century Dictionary.

• noun The act of presuming, or taking upon one's self more than good sense and propriety warrant; excessive boldness or over-confidence in thought or conduct; presumptuousness; assurance; arrogance.
• noun The act of presuming or probably inferring; hypothetical or inductive inference.
• noun That which is presumed; that which is supposed to be true upon grounds of probability.
• noun A ground for presuming or believing; evidence or probability, as tending to establish an opinion.
• noun In law, an inference as to the existence of one fact from the existence of some other fact, founded upon a previous experience of their connection, or dictated by the policy of the law.
• noun Surmise, Conjecture, etc. See inference.
• noun Likelihood, probability.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of presuming, or believing upon probable evidence; the act of assuming or taking for granted; belief upon incomplete proof.
• noun Ground for presuming; evidence probable, but not conclusive; strong probability; reasonable supposition.
• noun That which is presumed or assumed; that which is supposed or believed to be real or true, on evidence that is probable but not conclusive.
• noun The act of venturing beyond due beyond due bounds; an overstepping of the bounds of reverence, respect, or courtesy; forward, overconfident, or arrogant opinion or conduct; presumptuousness; arrogance; effrontery.
• noun See under Conclusive.
• noun (Law) an argument of a fact from a fact; an inference as to the existence of one fact not certainly known, from the existence of some other fact known or proved, founded on a previous experience of their connection; supposition of the truth or real existence of something, without direct or positive proof of the fact, but grounded on circumstantial or probable evidence which entitles it to belief.
• noun (Law) a postulate applied in advance to all cases of a particular class; e. g., the presumption of innocence and of regularity of records. Such a presumption is rebuttable or irrebuttable.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun the act of presuming, or something presumed
• noun the belief of something based upon reasonable evidence, or upon something known to be true
• noun the condition upon which something is presumed
• noun dated arrogant behaviour

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an assumption that is taken for granted
• noun a kind of discourtesy in the form of an act of presuming
• noun audacious (even arrogant) behavior that you have no right to
• noun (law) an inference of the truth of a fact from other facts proved or admitted or judicially noticed