なければならない
なければならない
expression
must; have to
1.
must; have to; cannot do otherwise
A grammatical pattern expressing necessity or obligation. Attaches to the negative stem of verbs and to nouns/na-adjectives via で. Literally "if (it is) not so, it will not do," but used straightforwardly to mean "must."
もう行かなければならない。
I have to go now.
明日までに書類を出さなければならない。
I have to submit the documents by tomorrow.
健康のために、毎日運動しなければならないと医者に言われた。
The doctor told me I have to exercise every day for my health.
Formed from the negative stem (e.g. 行か-) + ければならない. Conveys obligation, requirement, or unavoidable necessity. Typically a written or polite-spoken form; in casual conversation it is often shortened.
FORMATION:
- Verbs: drop ない from the plain negative, add ければならない (食べない → 食べなければならない)
- I-adjectives: drop final い from the negative stem, add くなければならない
- Nouns / Na-adjectives: + でなければならない
CASUAL CONTRACTIONS:
- なければ → なきゃ (食べなきゃ — gotta eat)
- なければならない → なきゃならない / なきゃいけない / なきゃ
SIMILAR EXPRESSIONS:
- なくてはならない: also "must" — slightly more formal feel; nearly interchangeable
- なくてはいけない: "must" — common in spoken Japanese
- ねばならない: "must" — literary/written register
REGISTER:
The full form なければならない sounds careful and is common in writing, announcements, and explanations of rules. In everyday conversation, contractions are far more frequent.