presumption

American  

[pri-zuhmp-shuhn] / prɪˈzʌmp ʃən /

noun

1. the act of presuming.

2. assumption of something as true.

3. belief on reasonable grounds or probable evidence.

4. something that is presumed; an assumption.

5. a ground or reason for presuming or believing.

6. Law. an inference required or permitted by law as to the existence of one fact from proof of the existence of other facts.

7. an assumption, often not fully established, that is taken for granted in some piece of reasoning.

8. unwarrantable, unbecoming, or impertinent boldness.

   Synonyms:

   gall, arrogance, effrontery, audacity

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presumption British  

/ prɪˈzʌmpʃən /

noun

1. the act of presuming

2. bold or insolent behaviour or manners

3. a belief or assumption based on reasonable evidence

4. a ground or basis on which to presume

5. law an inference of the truth of a fact from other facts proved, admitted, or judicially noticed

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Other Word Forms

• overpresumption
  noun

Etymology

Origin of presumption

1175–1225; Middle English: effrontery, supposition < Latin praesūmptiōn- (stem of praesūmptiō ) anticipation, supposition, Late Latin: presumptuousness, equivalent to praesūmpt ( us ) (past participle of praesūmere to undertake beforehand; see presume) + -iōn- -ion

Explanation

The noun presumption pretty much means jumping to conclusions. It is taking something for granted — an idea, an answer, an event — without having any real knowledge about it, and that is usually not a good thing. Making a presumption means assuming something is true or false without getting all the information necessary for verification. You can decipher this from the prefix pre, which means "before," together with the sume — from the Latin sumere, "to take." Because so many times a presumption turns out to be false, the word has a negative connotation to it; there's something reckless about making up your mind before you know all the facts.

Example Sentences

The presumption of the policy is that accused teachers would be reassigned to their home, not to teach a new group of students.

From Los Angeles Times • May 5, 2026

The law generally treats marriage as a financial partnership and the presumption is that assets will be equitably divided upon breakup.

From The Wall Street Journal • Apr. 20, 2026

She wrought real reputational harms and wrecked the presumption of regularity to the point where judges are now just saying: I just assume you lie all the time.

From Slate • Apr. 3, 2026

Whether Reece James, John Stones and Tino Livramento are fit enough to play every four days is a big presumption, of course.

From BBC • Mar. 29, 2026

In the same sense that our judicial system presumes us to be innocent until proved guilty, a medical-care system may work best if it starts with the presumption that most people are healthy.

From "The Lives of a Cell" by Lewis Thomas

Related Words

• assumption
• likelihood
• premise
• supposition
• suspicion