JLPT N5 · Guessing & hearsay
だろう (darou)
～だろう — “probably ～”
In short · The plain-style way of guessing “probably ～.” It is the casual counterpart of でしょう and is used in monologues, with close friends, and in writing.
Pattern
-
動詞・い形容詞の普通形＋だろうVerb or い-adjective plain form + だろう (食べるだろう, 高いだろう) -
名詞・な形容詞（語幹）＋だろうNoun or な-adjective stem + だろう (先生だろう, 静かだろう)
Where it comes from
だろう is the guessing form of だ. It attaches straight to plain forms (食べる, 高い). After a noun or な-adjective, no extra だ is inserted (先生だろう).
When to use it
It is used for predictions and for guesses about things you cannot see for sure. In speech, だろうね or だろう？ can also ask for the listener’s agreement.
Difference from でしょう
The meaning is the same, but だろう is plain. When you speak politely, especially to someone senior, use でしょう.
Examples
-
明日（あした）は晴（は）れるだろう。
Ashita wa hareru darō.
It will probably be sunny tomorrow.
-
この店（みせ）は高（たか）いだろう。
Kono mise wa takai darō.
This shop is probably expensive.
-
あの人（ひと）は先生（せんせい）だろう。
Ano hito wa sensei darō.
That person is probably a teacher.
Common mistakes
- Do not use it for facts you know for sure. For certain things, state them plainly with です.
- Do not add だ before だろう after a noun or な-adjective (not 先生だだろう).
More grammar points
- でしょう ～でしょう — a polite “probably ～ / right?”
- は は (wa) — the topic particle
- を を (o) — the object particle
- に に (ni) — time, destination, location
- で で (de) — place of action & means
- と と (to) — and / together with
- の の (no) — possessive & noun linker
- へ へ (e) — direction
- も も (mo) — also / too
- か か (ka) — the question marker
- です です (desu) — the copula
- から から・まで — from … to …
- より より (yori) — than (comparison)
- ます 〜ます — the polite verb form
- て て-form — connecting & requests
- ない ない-form — the plain negative
- た た-form — the plain past
- い い-adjectives
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