だろう
Right?, Probably, Isn't it?
Structure
Adjective + だろう
Noun + だろう
Explanation
だろう is derived from the plain copula だ. In casual speech, it is often shortened to だろ. だろう is used to express the speaker's assumption or belief about something, often with the implication that the listener will share the same opinion. In English, this is similar to saying 'probably' or adding a tag question like 'right?'.
- 彼、今日映画に行くだろ？He's going to the movies today, right?
- 次の試合は勝つだろう。We'll probably win the next game.
だろう has the same essential function as its polite equivalent, でしょう. However, since だ is the plain form of です, だろう is considered more informal and can have a masculine connotation in comparison to でしょう.
Caution
Although だろう is frequently used when the speaker has some evidence to back up their claim, it can also be used to express a simple hunch or a gut feeling about something.
- 明日の試験は簡単だろう？The test tomorrow will be easy, won't it?
When a sentence expresses a 'hunch' like this, だろう may imply a fairly low level of confidence. The speaker's intonation will usually clarify how certain they actually are.
Examples
この鞄は重いだろう？
This bag is heavy, isn't it?
犯人は彼だろう。
The culprit is him, right?
あれは駅だろう。
That over there is the station, isn't it?
明日は、寒いだろう。
It will probably be cold tomorrow.
それは、嘘だろう。
That's a lie, isn't it?
ここが入口だろう？
This is the entrance, right?
明日は、休日だろう。
Tomorrow is a holiday, isn't it?
これは間違いだろう。
This is a mistake, isn't it?
冗談だろう。
You're kidding (right?)
田中さんも学生だろう。
Tanaka-san is also a student, right?
この部屋は暑いだろう。
This room is hot, isn't it?
そっちの方が安いだろう。
That one is cheaper, (right?)
それが理由だろう。
That's probably the reason.