How to say "certain" in Japanese
Choosing the right word
- 確かたしかna-adjectiveThe word for stating that you are sure or positive something is true, as when you are certain you locked the door. It centers on the speaker's own conviction.
- 確実かくじつna-adjective, nounCovers 'certain' as an objective quality: definite and reliable, with no risk of failure. Use it when the certainty lies in the thing itself, as with a plan or method you can count on.
- 某ぼうnoun, prefixNot a way of saying you are sure: this is the 'certain' of 'a certain person', used to refer to a person or thing whose name is not given or is withheld.
- 必然ひつぜんno-adjective, na-adjectiveCovers 'certain' through the idea of necessity: what follows inevitably and cannot be otherwise. Use it for outcomes bound to happen as a necessary result, not for what you merely feel sure of.
- 必至ひっしna-adjective, no-adjectiveThis is 'certain' as in unavoidable: an outcome bound to come about, with no way left to escape it. Use it when declaring a result inevitable.
Use 「確か」 for what you feel sure of, 確実 for what is definite and reliable, 必然 for what follows necessarily, 必至 for what cannot be avoided, and 某 only for 'a certain' person or thing.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Japanese equivalents
See also
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