出す|だす
- 1To start doing something suddenly or unexpectedly; to burst into an action.Ex. 1
- 2For a natural phenomenon or event to begin abruptly.Ex. 2
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Used in both speech and writing to describe the abrupt start of actions, emotions, or natural phenomena, often ones outside the speaker's control, such as crying, laughing, running, or rain. It frequently appears with adverbs such as 急に or いきなり, which reinforce the suddenness. Compared with 〜始める, which neutrally marks a beginning, 〜出す highlights an unexpected, sudden onset.
Learners often use 〜出す for planned, deliberate beginnings, where the neutral 〜始める is more natural.
Note that 出す attaches to the ます-stem with ます removed (泣き出す), not to the dictionary form or て-form.
- 始めるN4「始める」attaches the same way and simply states that something begins, without emphasizing suddenness or momentum; it is also common for gradually unfolding, ongoing actions, as in「毎日勉強し始めた」. For events like crying or rain,「始める」and「出す」are often interchangeable, but「出す」makes the suddenness more explicit.
- いきなりN2「いきなり」is an adverb that modifies the predicate (or appears as「いきなりの」) and means something happens with no warning or without any build-up, while「〜出す」attaches to the ます-form and marks the start of an action. They cannot replace each other but are often used together:「いきなり泣き出す」.
- 急にN4「急に」is an adverb placed before the predicate to mean 'suddenly,' and it can also modify changes like「寒くなる」, whereas「出す」attaches to the ます-form and marks the start of an action. They play different roles and cannot replace each other, but they are often used together, as in「急に泣き出す」.
- たとたんN3「たとたん」attaches to the verb た-form and links two events, meaning the second event occurs the moment the first one has just happened, while「出す」attaches to the ます-form and only marks the start of a single action. They cannot replace each other, but they can be used together, as in「座ったとたん泣き出した」.
- かけるN3「かける」also attaches to the ます-form, but it describes an action left half-finished (「読みかけの本」) or something that almost happened (「死にかける」); its focus is not the moment of starting, so it cannot replace「出す」.
Unlike 〜始める (a neutral beginning, including planned actions) and 〜かける (an action about to start or left half-done), 〜出す stresses a sudden start, and 急に and いきなり are adverbs that often accompany it. たとたん instead links two events, with the second happening right as the first occurs.


