presume

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

• intransitive verb To take for granted as being true in the absence of proof to the contrary.
• intransitive verb To constitute reasonable evidence for assuming; appear to prove.
• intransitive verb To venture without authority or permission; dare.
• intransitive verb To take for granted that something is true or factual; make a supposition.
• intransitive verb To act presumptuously or take unwarranted advantage of something.

from The Century Dictionary.

• To take upon one's self; undertake; venture; dare: generally with an infinitive as object.
• To believe or accept upon probable evidence; infer as probable; take for granted.
• Synonyms Surmise, Guess, etc. (see conjecture), think, consider.
• To be venturesome; especially, to venture beyond the limits of ordinary license or propriety; act or speak overboldly.
• To press forward presumptuously; be led by presumption; make one's way overconfidently into an unwarranted place or position.
• To take; to take to oneself: with of.

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

• transitive verb To assume or take beforehand; esp., to do or undertake without leave or authority previously obtained.
• transitive verb To take or suppose to be true, or entitled to belief, without examination or proof, or on the strength of probability; to take for granted; to infer; to suppose.
• intransitive verb To suppose or assume something to be, or to be true, on grounds deemed valid, though not amounting to proof; to believe by anticipation; to infer.
• intransitive verb To venture, go, or act, by an assumption of leave or authority not granted; to go beyond what is warranted by the circumstances of the case; to venture beyond license; to take liberties; -- often with on or upon before the ground of confidence.

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

• verb take upon oneself; act presumptuously, without permission
• verb take liberties or act with too much confidence
• verb constitute reasonable evidence for
• verb take to be the case or to be true; accept without verification or proof