1. lightning fast - Adjective
2. lightning fast - Adverb
3. lightning fast - Phrase
lightning fast (not comparable)
(idiomatic) Extremely fast, fast as lightning.
Synonyms: fulgurant, lightning-quick, quick as a flash, in a flash
lightning fast (not comparable)
(idiomatic) Extremely quickly.
Synonyms: quick as a flash, in a flash, lightningly