A synonym for "very fast" is quick.
Slow and fast are antonyms; a synonym is a word with a similar meaning.
fast
fast
Agile is a synonym of fast. Athletic is a synonym of fast.
fast; quick
Synonyms.
Courages brave very sexy good with girls fast runner a beast on the court and the field
fast, starvation, dietary, regime
quick, speedy, at once
fast, quick, speedy, rapid, ...
well a synonym would be a restaurant and a antonym would be a fast food restaurant
fast, quickly, briskly, hastily, promptly