assume

American  

[uh-soom] / əˈsum /

verb (used with object)

assumed, assuming

1. to take for granted or without proof.

   to assume that everyone wants peace.

   Synonyms:

   posit, postulate, presuppose, suppose

2. to take upon oneself; undertake.

   to assume an obligation.

3. to take over the duties or responsibilities of.

   to assume the office of treasurer.

4. to take on (a particular character, quality, mode of life, etc.); adopt.

   He assumed the style of an aggressive go-getter.

5. to take on; be invested or endowed with.

   The situation assumed a threatening character.

6. to pretend to have or be; feign.

   to assume a humble manner.

7. to appropriate or arrogate; seize; usurp.

   to assume a right to oneself; to assume control.

8. to take upon oneself (the debts or obligations of another).

9. Archaic. to take into relation or association; adopt.

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verb (used without object)

assumed, assuming

1. to take something for granted; presume.

assume British  

/ əˈsjuːm /

verb

1. (may take a clause as object) to take for granted; accept without proof; suppose

   to assume that someone is sane

2. to take upon oneself; undertake or take on or over (a position, responsibility, etc)

   to assume office

3. to pretend to; feign

   he assumed indifference, although the news affected him deeply

4. to take or put on; adopt

   the problem assumed gigantic proportions

5. to appropriate or usurp (power, control, etc); arrogate

   the revolutionaries assumed control of the city

6. Christianity (of God) to take up (the soul of a believer) into heaven

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Usage

What's the difference between assume and presume? Assume and presume have very similar meanings—they both mean to suppose that something is true without being able to confirm it. Assume, however, usually implies that the conclusion reached by the person doing the assuming is not based on much. Presume, on the other hand, often implies that the conclusion is based on something a bit stronger, such as some evidence or past situations in which the same thing happened. For example, you might presume that someone will be attending a meeting because they always attend and you have no reason to think they won’t be there. The word assume could also be used in this scenario, but it’s most likely to be used in situations in which there was less of a reason to have come to a certain conclusion. For example, you might assume something about someone you’ve just met based only on how they look (which is never a good idea). A good way to remember this difference in how the two words are used is that the prefix pre- in presume means “before”—when you presume things, you’re often basing that presumption on something that has happened before. As for assume, well, we’ll just assume you know a good way of remembering how it’s used. Assume and presume also have a few meanings that don’t overlap. Assume can mean to take on, adopt, or be endowed with something, as in I don’t want to assume any new responsibilities. Presume can mean to undertake or do something without permission or justification, as in I don’t presume to speak for the entire class. Here are examples of assume and presume used correctly in a sentence. Example: I assumed you knew what you were doing when you volunteered to bake the cake, but apparently I shouldn’t have. Example: I presumed, based on your resume, that you knew how to work with this software. Want to learn more? Read the full breakdown of the difference between assume and presume.

Related Words

See pretend.

Other Word Forms

• assumable adjective
• assumer noun
• overassume verb (used with object)
• preassume verb (used with object)
• reassume verb (used with object)

Etymology

Origin of assume

First recorded in 1400–50; late Middle English (from Anglo-French assumer ), from Latin assūmere “to take to, adopt,” equivalent to as- “toward” + sūmere “to take up”; as-, consume

Explanation

Assume isn't only used to mean "accept as truth without checking"; it also means "take on the form of." It might be safer if you don't assume that the vampire standing in front of you isn't merely a person assuming that form. Assume always has the sense of taking on something. It may be the belief in the appearance of truth: Your mother probably assumes you do your homework right after school. It may be another form or identity: Superman assumes the identity of a city reporter. Or, it might be a physical space: If you get nervous while driving, your dad might assume control of the car.

Example Sentences

"We assume that the plants have an unlimited amount of water even with less-than-average precipitation, because they have access to snowmelt."

From Science Daily • Apr. 14, 2026

I was born and raised in L.A., but actually, a lot of Eritreans, when they first meet my sister and myself, assume we were born back home.

From Los Angeles Times • Apr. 13, 2026

At some point before the 2 June primary, "I assume somebody will stick out," Casey said.

From BBC • Apr. 13, 2026

Investors can also take comfort from the fact that the fund’s managers do not assume an inordinate amount of risk.

From Barron's • Apr. 9, 2026

Theo scans the street, to make sure nobody is watching my breakdown, I assume.

From "The Brightwood Code" by Monica Hesse

Related Words

• accept
• conclude
• consider
• estimate
• expect
• guess
• infer
• presume
• speculate
• suspect
• think
• understand