aspect N4 common casualpolitewritten
〜出す — suddenly start ~ing / burst into ~ing
〜出す ・ だす
Builds on 連用形（ます形）
Meaning
- suddenly start ~ing / burst out ~ing — an abrupt, often unexpected onset
Key sentence
彼女は突然笑い出した。
She suddenly burst out laughing.
Formation
| Attaches to | Form | Example |
|---|---|---|
| Verb (ます-stem) | V-stem + 出す | 走る → 走り出す |
Examples
子どもが急に泣き出した。
The child abruptly started crying.
空が暗くなって、雨が降り出した。
The sky darkened and it started pouring.
みんなが一斉に走り出した。
Everyone broke into a run all at once.
When you can't use it
- 出す highlights an uncontrolled, spontaneous onset, so it sits awkwardly with a planned or willed beginning. 'I'll start studying tomorrow' is 明日から勉強し始める, not 〜し出す.
Easily confused with
See 〜出す in real sentences
Jengo shows 〜出す 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 Basic Japanese Grammar.