Translation guide
The concept of something being necessary, unavoidable, or required. In Japanese, this is expressed through nouns, adjectives, and grammatical patterns that convey obligation, inevitability, or essential need.
Expressing that something is necessary or needed in a general sense.
The most common and versatile word for 'necessity' or 'need'. Can be used as a noun or na-adjective.
Water is necessary for living.
Emphasizes the quality or degree of necessity. Often used in formal or analytical contexts.
Means 'indispensable' or 'essential'. Stronger than 必要, implying something cannot be done without.
Expressing that someone must do something, or that an action is obligatory.
Standard pattern for 'must' or 'have to'. Used for both personal obligations and general rules.
Expressing that something is inevitable or certain to occur.
Expressing that something is a necessary condition or requirement.
Means 'required' or 'mandatory'. Often used for items, conditions, or qualifications.
Expressing that something is not necessary or there is no need to do it.
必要 (necessary) is the general term. 不可欠 (indispensable) is stronger and often used for things absolutely essential.
Water is necessary, but coffee is not indispensable.
There is a need to practice more.
Please explain the necessity of this plan.
酸素は生命に不可欠だ。
Oxygen is indispensable for life.
I have to submit the report by tomorrow.
Slightly more colloquial than ～なければならない. Very common in spoken Japanese.
I have to go now.
Expresses 'should' based on moral duty, advice, or natural expectation. Softer than 'must'.
You should listen to your parents.
Formal/literary pattern meaning 'cannot help but do' or 'have no choice but to'. Used for unavoidable actions.
I have no choice but to accept the facts.
Noun or na-adjective meaning 'inevitable' or 'necessary consequence'. Often used in logical or philosophical contexts.
Failure is an inevitable step toward success.
Expresses strong certainty or conviction that something is the case. 'Must be' or 'no doubt'.
He must know the truth.
Indicates expectation based on reasoning. 'Should' or 'ought to' in the sense of logical necessity.
She should have arrived by now.
Experience is required for this job.
Formal term for 'requirement' or 'necessary condition'. Used in business or legal contexts.
Do you meet the application requirements?
There's no need to rush.
Casual and common way to say 'don't have to' or 'it's okay not to'.
You don't have to come if it's inconvenient.
English 'necessity' can sometimes be translated directly as 必要性, but in many cases natural Japanese uses 必要 or a grammatical pattern like ～なければならない instead of a noun.