assumption
gb/əsˈʌmpʃən/ us/əsˈʌmpʃən/
B2
English
~ 1800
Senses
0 senses
Noun
B2
entity
1
belief without proof
An idea you think is true, but you do not have proof.
Usage pattern:
make [an assumption] about [something]
Common mistake:
Learners sometimes confuse 'assumption' with 'guess'. A guess is often less certain and may not be based on reasoning, while an assumption is usually a starting point for thinking or action.
Synonyms
presumption (Often suggests a stronger or more confident belief without proof.)
|
supposition (More formal; often used in academic or careful speech.)
Antonyms
fact (A statement that can be proven true, unlike an assumption.)
|
certainty (A state of being sure, which contrasts with accepting something without proof.)
Collocations
make an assumption
|based on the assumption
|challenge an assumption
|question an assumption
Themes
thinking
|communication
|logic
|core_vocabulary
|education
Examples
- Her decision was based on the assumption that he would agree.
- We cannot operate on the assumption that nothing will go wrong.
- That’s a dangerous assumption to make without evidence.
- He acted under the false assumption that she was single.
Learner examples
- I made the assumption that he was at home.
- She works on the assumption that the plan will succeed.
- It is only an assumption, not a fact.
- They made an assumption about his skills.
Noun
formal
C1
action
2
taking control or duty
The act of starting to have a job, power, or responsibility.
Usage pattern:
the assumption of [responsibility/office/duties]
Common mistake:
Learners may confuse this with 'acceptance'. 'Assumption' here emphasizes the start of holding a role, while 'acceptance' focuses on agreeing to take it.
Synonyms
acceptance (Focuses more on agreeing to take something rather than actively beginning it.)
|
undertaking (Emphasizes agreeing to do or take responsibility for something.)
Antonyms
relinquishment (The act of giving up power or responsibility.)
|
abdication (Formally giving up a position of power or duty.)
Collocations
assumption of responsibility
|assumption of office
|assumption of power
Themes
business
|politics
|work
Examples
- His assumption of office was marked by a formal ceremony.
- The assumption of responsibility came sooner than expected.
- The general's assumption of command changed the course of the battle.
Learner examples
- Her assumption of the job surprised many people.
- The president’s assumption of power happened last year.
- His assumption of duty was quick and smooth.
Noun
literary
C2
action
3
seizing without right
Taking something when you do not have the right to do so.
Synonyms
usurpation (Strongly implies wrongful or illegal seizure of power or rights.)
Antonyms
permission (Having consent to take or use something.)
Collocations
assumption of rights
|assumption of authority
Themes
law
|ethics
|core_vocabulary
Examples
- Their assumption of authority angered the committee.
- He was accused of the unlawful assumption of property rights.
- Such an assumption of power cannot be tolerated.
Learner examples
- His assumption of the land was wrong.
- The assumption of power was against the law.
- Their assumption of control upset many people.
Grammar
Dictionary form
assumption
IPA
GB/əsˈʌmpʃən/
US/əsˈʌmpʃən/
Syllables & stress
as - sump - tion (3 syllables)
Stress on 2nd syllable (sump)
Word forms
Noun
- Base: assumption
- Plural: assumption, assumptions
Word family
Forms
assumptions
noun
Core family
assume
verb B1
Related words
presumption
noun C1
presume
verb B2
Negative and opposite forms
unassuming
adjective
Advanced or less common
assumptive
adjective
Expressions
a false assumption
1/ə fˈɔls əsˈʌmpʃən/
fixed phrase
wrong belief without proof
A belief that is not correct, but is accepted as true.
Examples
- It’s a false assumption that all rich people are happy.
- Their plan failed because it was based on a false assumption.
make an assumption
1/mˈeɪk ən əsˈʌmpʃən/
fixed phrase
form belief without proof
To decide in your mind that something is true, without proof.
Examples
- Don’t make an assumption about her intentions before asking.
- I made an assumption that he would help me.
on the assumption that
1/ˈɔn ðə əsˈʌmpʃən ðˈæt/
fixed phrase
believing something without proof
Believing something is true and acting because of that belief.
Examples
- We started early on the assumption that traffic would be heavy.
- They invited extra guests on the assumption that some would not come.