同士
Fellow, With each other, Mutually, Between, Among, Together, With
Structure
Noun + 同士 + の + Noun
Explanation
The noun 同士, meaning 'fellow', can be used like a suffix. When attached to another noun, it indicates a sense of mutuality, such as 'among (A)', 'fellow (A)', or '(A)s together'.
To use 同士, connect it directly to a noun. This creates a new noun phrase that describes a shared status or relationship. The structure (noun + 同士 + の + noun) is also very common, showing that the second noun pertains to the first group.
- これは学生同士のけんかだから、先生は口を出さないでください。This is a fight between students, so teacher, please stay out of it.
- 親戚同士で集まって、よくゲームをしました。We relatives would often get together and play games.
- それは男同士の秘密だから、誰にも言えないよ。That's a secret between us guys, so I can't tell anyone.
- 他人同士なんだから、プライベートなことを聞くのはやめなさい。We're strangers to each other, so stop asking such personal questions.
同士 generally highlights two specific kinds of 'mutuality'. They are:
種類 - Type. (A) and (B) are of the same kind.
関係 - Relationship. (A) and (B) share a specific connection.
- 二人は外国人同士だから、気持ちがよくわかるみたい。Since they are both foreigners, it seems they understand each other well.
- それは夫婦同士の問題だから、他の人は関係ないよ。That's an issue between the married couple, so other people shouldn't get involved.
Caution
同士 is most often applied to 'people' or 'living things' that have a shared identity or relationship, rather than inanimate objects. A helpful reminder is the kanji 士, which means 'gentleman'. Nevertheless, it is sometimes used when referring to non-living things as well.
- この接着剤は木同士はよく付くけど、金属同士はあまり付かない。This adhesive works well for bonding pieces of wood together, but it doesn't work so well for bonding metal. (Natural, but not very common)
- 彼らは良きライバル同士として、お互いに成長してきた。As good rivals to each other, they've pushed one another to grow. (Natural)
Examples
隣人同士なんだから、あいさつぐらいはしようよ。
We're fellow neighbors, so we should at least greet each other.
兄弟同士でそんなにいがみ合うのはやめなさい。
Stop bickering so much with each other; you're brothers!
恋人同士なんだから、秘密なんてないはずだ。
There shouldn't be any secrets between lovers.
彼らはライバル同士だが、互いを尊敬し合っている。
Although they are rivals, they have a mutual respect for one another.
学生同士で協力して、この問題を解きましょう。
Let's work together as students to solve this problem.
独身同士、気楽なもんだよね。
It's a carefree life for us fellow single people, isn't it?
災害時には、見知らぬ人同士が助け合う光景が見られた。
During the disaster, there were scenes of total strangers helping one another.
これは夫婦同士の問題だから、口を出さないでください。
This is a problem between a husband and wife, so please don't interfere.
部員同士の仲が悪くては、チームは強くなれない。
If the relationship among the club members is bad, the team can't become strong.
他人同士が一つの屋根の下で暮らすのは大変だ。
It's difficult for strangers to live together under one roof.
子ども同士のけんかに親が出てくるものではない。
Parents shouldn't get involved in fights between children.
車同士が衝突して、大きな音がした。
Two cars collided with each other, making a loud noise.