かんぱつをいれず· also かんはつをいれず
immediately; instantly; with nary a pause; without a moment's delay
Also written 間髪をいれず、間髪を容れず
Expression
トムは間髪かんぱつを入いれず、返答へんとうした。
Tom responded instantly.
間髪かんぱつを入いれず、迅速じんそくかつ的確てきかくな応対おうたい、畏おそれ入いります。
Such an accurate, lightning-quick reply. What can I say?