Translation guide
The English verb "assume" has several distinct meanings. This guide helps learners choose the right Japanese expression based on the intended meaning: taking on a role or responsibility, supposing something without proof, or adopting a particular attitude or appearance.
assume a role
assume responsibility
To begin to have a particular job, position, or responsibility.
Used when formally assuming a position or office, such as a presidency or directorship.
He will assume the position of president next month.
General term for taking on a task, responsibility, or role. Can be used in both formal and casual contexts.
To shoulder or bear a responsibility, often with a sense of duty. Slightly more literary.
To think that something is true or will happen, although you have no proof.
To assume for the sake of argument or as a premise. Common in logical or hypothetical contexts.
Let's assume he is guilty.
To assume firmly, often incorrectly or without basis. Implies a subjective belief.
To jump to a conclusion and act on that assumption, often with a negative nuance.
To guess or infer based on available information. Less strong than 'assume' in English, but often used in similar contexts.
A grammatical pattern meaning 'to assume/suppose that...'. Used in hypothetical or conditional statements.
To begin to have a particular quality, appearance, or name, often deliberately or temporarily.
To put on an appearance or pretense; to feign. Often used for attitudes or emotions.
He assumed an air of calmness.
To take on a certain quality or characteristic, often gradually or inherently.
To assume a name; to call oneself by a particular name.
While 仮定する is correct for logical assumptions, using it for casual guesses like 'I assume you're busy' sounds unnatural. Use 思う (to think) or だろう (probably) instead.
I assume you're busy.
Both mean to assume, but 思い込む focuses on a fixed belief (often mistaken), while 決めてかかる implies acting on that assumption, often confrontationally.
She assumed the role of leader for the project.
He assumes a heavy responsibility.
She assumes I'm lying.
He assumes I will fail.
The police assume he is the culprit.
Assuming he doesn't come, we'll have to change the plan.
The words assumed a sarcastic tone.
He assumed a false name.