JLPT N3Everyday

同どう士しamong themselves; with each other

After a word for what people are, 同どう士し means those people with one another, and nobody else: friends with each other, children among themselves, just us women.

二人ふたりは友とも達だち同どう士しです。

The two of them are friends.

子こども同どう士しのけんかに、大人おとながすぐ口くちを出だす必ひつ要ようはない。

When children quarrel among themselves, adults don't need to step in straight away.

How to form it

Noun + 同どう士し

Straight on, with no の before it. The result is a noun: 友とも達だち同どう士しだ, 友とも達だち同どう士しで行いく, 友とも達だち同どう士しの約やく束そく.

Before it: What they are to each other, or what they all are: 友とも達だち, 恋こい人びと, 隣となり, 子こども, 女おんな, 男おとこ, 初しょ対たい面めん (meeting for the first time).
How many: Two people or a whole group. Things too: 車くるま同どう士しがぶつかった, two cars hit each other.
Where you'll meet it: Everyday talk and writing.

In use

年ねん齢れいの近ちかい社しゃ員いん同どう士しで、新あたらしい企き画かくについて話はなし合あった。

Employees of about the same age talked the new project over among themselves.

初しょ対たい面めん同どう士しなので、最さい初しょは会かい話わが少すこしぎこちなかった。

They were meeting for the first time, so the conversation was a little awkward at first.

たまには女おんな同どう士しで旅りょ行こうに行いきたいね。

It would be nice to go on a trip sometime, just us women.

Two things to know

What it adds to 友とも達だちと

友とも達だちと旅りょ行こうに行いった。

I went on a trip with a friend.

と names who came with you.

友とも達だち同どう士しで旅りょ行こうに行いった。

We went on a trip, just us friends.

同どう士し says what the group was: friends and nobody else. No parents, no teachers.

It takes in both sides

English "fellow" can describe one person: a fellow student. 同どう士し can't. It always names everyone in the relationship together.

Not said: 田た中なかさんは私わたしの友とも達だち同どう士しです。

(Tanaka is a friend of mine.)

田た中なかさんは私わたしの友とも達だちです, or 田た中なかさんと私わたしは友とも達だち同どう士しです.

Close neighbours

たちN5

Just a group: the students, Tanaka and the others. 同どう士し is not a plural. The word before it is what links the people, and the sentence is about them with one another.

田た中なかさんたちは先さきに帰かえりました。

Tanaka and the others went home ahead of us.

合あうN3

Goes on the verb: they do it to each other. The two often come together.

留りゅう学がく生せい同どう士しが集あつまって、生せい活かつ上じょうの悩なやみを話はなし合あった。

The international students got together and talked over the problems of daily life.

Check yourself

1Who went to Kyoto?

夏なつ休やすみに、学がく生せい同どう士しで京きょう都とへ行いった。

Choose an answer to see why.

2"Tanaka is a colleague of mine."

Choose an answer to see why.

3Which one fits?

これは（　　）約やく束そくだ。

Choose an answer to see why.

More detail

隣となり同どう士し is "next to each other". 似にた者もの同どう士し is "two of a kind".

二人ふたりは席せきが隣となり同どう士しで、すぐ仲なか良よくなった。

Their seats were next to each other, and they soon became friends.

あの二人ふたりは似にた者もの同どう士しだ。

Those two are two of a kind.

More sentences

学がく生せい同どう士しの交こう流りゅうを増ふやすため、月つきに一いち度どイベントを開ひらいている。

We hold an event once a month so that students have more contact with one another.

同おなじ趣しゅ味みを持もつ者もの同どう士し、すぐに話はなしが合あった。

Sharing the same hobby, they hit it off at once.

ライバル同どう士しが互たがいの健けん闘とうをたたえた。

The rivals praised each other's efforts.

田た中なかさんと森もりさんは同どう僚りょう同どう士しです。

Tanaka and Mori are colleagues.