迅速じんそく Common I-adj Noun English jmdict 1 adjectival nouns or quasi-adjectives (keiyodoshi)noun (common) (futsuumeishi) (very) quick;rapid;swift;speedy;prompt;expeditious 間髪を入れず、迅速かつ的確な応対、畏れ入ります。 Such an accurate, lightning-quick reply. What can I say?