This is the 10770th most frequent French word.
neuve
"Neuve" means "new" (feminine form).
'Neuve' here describes the state of the car being newly manufactured or unused.
J'ai acheté une voiture neuve hier.
I bought a new car yesterday.
'Neuf' (masculine form of 'neuve') is used to indicate the book is unused, reflecting the adjective's core meaning.
Ce livre est neuf, il n'a jamais été ouvert.
This book is new; it has never been opened.
'Neuves' describes the innovation or novelty of ideas, not their physical condition but their conceptual newness.