modality N5 essential casualpolitewritten
だろう — probably ~ (conjecture)
だろう
Meaning
- probably ~ / I suppose ~ — the speaker's conjecture about something not yet confirmed
Key sentence
明日は晴れるだろう。
It'll probably be sunny tomorrow.
Formation
| Attaches to | Form | Example |
|---|---|---|
| Plain form / noun / na-adjective | plain V/A + だろう; N or na-adj + だろう (no だ) | 来るだろう / 学生だろう / 静かだろう |
When: Plain だろう can sound assertive or masculine in conversation; でしょう is the neutral polite equivalent.
Examples
彼はもう家に着いただろう。
He's probably arrived home by now.
この問題は難しいだろう。
This problem is probably difficult.
Easily confused with
でしょう Same conjecture, different register: だろう is plain, でしょう polite. 〜かもしれない だろう is a fairly confident guess ('it'll probably ~'); かもしれない is lower certainty ('it might ~, it might not'). 〜はず はず is an expectation grounded in concrete evidence or logic ('it should be, given X'); だろう is a looser personal guess with no such grounding required.
Notes
- Said with rising intonation, 〜だろう？ instead seeks the listener's agreement: 'it's ~, right?'
See だろう in real sentences
Jengo shows だろう the way you actually meet it: inside real Japanese sentences, so it sticks instead of staying an abstract rule.
Study it in JengoSources Compiled with reference to A Dictionary of Intermediate Japanese Grammar.