unconsciously; involuntarily; without thinking
Describes an action or reaction that happens before one is aware of it, often driven by emotion or instinct. Common in spoken and written Japanese.
I couldn't help but cry at the final scene of that movie.
彼の冗談に思わず笑ってしまった。
I laughed involuntarily at his joke.
It was so funny that I couldn't help laughing.
I was so surprised that I let out a gasp before I could stop myself.
Hearing that story, I found myself tearing up.
The cake looked so delicious that I instinctively reached for it.