This is the 10576th most frequent French word.
manquantes
"Missing."
In this sentence, 'manquantes' describes pages that are missing or absent, behaving as an attribute of 'pages' (feminine plural noun). It agrees in gender and number with the noun.
Les pages manquantes du livre rendent l'histoire difficile à suivre.
The missing pages of the book make the story hard to follow.
Here, 'manquantes' qualifies 'informations', which is a feminine plural noun, indicating that certain information data is absent and needs locating.
Nous devons trouver les informations manquantes pour compléter le rapport.
We need to find the missing information to complete the report.
In this usage, 'manquante' describes the 'pièce' (feminine singular noun) and signifies that this particular piece was absent but has now been found, agreeing in gender and number.