とっさに

とっさに is an adverb meaning "instinctively," "reflexively," or "in the spur of the moment." It describes an action taken immediately and without deliberate thought in response to a sudden situation. The emphasis is on the spontaneous, reflexive nature of the reaction rather than simply doing something quickly.

This distinguishes とっさに from words like すぐに (right away) or ただちに直ちに (immediately), which focus on speed but don't necessarily imply an instinctive or reflexive response. とっさに is used when someone reacts automatically – often before they even have time to think.

Common patterns

とっさに is used with verbs describing physical reactions (dodging, grabbing, shielding) and verbal reactions (answering, lying):

とっさの + Noun

とっさに can also appear in its attributive form とっさの to modify nouns directly, meaning "split-second" or "spur-of-the-moment":

Negative contexts

とっさに is also common in negative sentences, expressing that someone couldn't react or respond in time:

Note the use of には here, which adds emphasis to the idea that "in that particular moment" something was impossible.