Synonyms of instantaneous in English:

instantaneous


See definition of instantaneous

adjective

1‘it may be difficult for you to make an instantaneous response to what is said’

SYNONYMS

immediate, instant, on-the-spot, prompt, direct, swift, speedy, rapid, quick, expeditious, express, lightning

sudden, hurried, hasty, precipitate, abrupt

informal snappy

literary fleet, rathe

rare alacritous

ANTONYMS

delayed, long-term