Translation guide
This English idiom means 'immediately, without hesitation, or at the slightest provocation.' Japanese has no single direct equivalent, so learners should use expressions that convey the intended nuance: willingness, suddenness, or a trigger.
To say that someone will do something right away, without needing to be asked twice, often with enthusiasm.
The most straightforward way to say 'immediately.' It's neutral and can be used in most contexts.
He'll help you at the drop of a hat if you ask.
Literally 'with a two-word reply,' implying an immediate and willing 'yes.' It emphasizes eagerness.
She accepted at the drop of a hat.
Means 'willingly' or 'readily.' Often used with verbs like 引き受ける (to accept) or 手伝う (to help).
He agreed to the offer at the drop of a hat.
To describe someone who reacts instantly to a small stimulus, often in a negative or emotional way.
To emphasize that something happens suddenly, without warning or planning.
The standard word for 'suddenly.' It fits when the focus is on the abruptness of the action.
He started singing at the drop of a hat.
More colloquial than 突然, implying something happening out of the blue, often with a sense of surprise or rudeness.
Do not try to translate 'drop of a hat' literally into Japanese. Phrases like 帽子を落とす (to drop a hat) will not be understood idiomatically.
すぐに focuses on the short time before an action, while 突然 emphasizes the unexpectedness. Choose based on whether you want to highlight speed or surprise.
She starts crying at the drop of a hat.
Means 'at every opportunity' or 'for any reason.' It implies a habitual, often annoying, readiness to react.
He complains at the drop of a hat.
彼はいきなり会社を辞めた。
He quit his job at the drop of a hat.