～出す
suddenly start to
～出す（～だす）attaches to the ます-stem of a verb and means that the action begins suddenly or unexpectedly: 泣き出す “burst into tears”, 降り出す “start to rain”.
English usually translates this as “suddenly started to ...” or “burst out ...”. The similar pattern ～始める is a neutral “begin to”, while ～出す adds the feeling that the start was abrupt and often unplanned.
A sudden, unexpected start
Use ～出す when something kicks off all at once, often catching people off guard.
赤ちゃんが急に泣き出した。
“The baby suddenly started crying.”
- 赤ちゃん（あかちゃん）= baby
- が = subject marker
- 急に（きゅうに）= suddenly
- 泣き出した（なきだした）= burst into tears
家に帰る途中で、雨が降り出した。
“On my way home, it started to rain.”
- 家（いえ）= home
- に = direction marker
- 帰る（かえる）= to return
- 途中で（とちゅうで）= on the way
- 雨（あめ）= rain
- が = subject marker
- 降り出した（ふりだした）= started to fall
How to form it
Verb ます-stem + 出す
- 泣く（なく）= to cry → 泣き出す（なきだす）= burst into tears
- 降る（ふる）= to fall (rain) → 降り出す（ふりだす）= start to rain
- 走る（はしる）= to run → 走り出す（はしりだす）= break into a run
Key idea
～出す marks the moment something bursts into action. If 始める is a calm “begin”, 出す is the action suddenly leaping out into the open.
Other N3 grammar
Updated .