The adjective in French, like in English or in Hindi, is a word that specify a noun or a pronoun. It can be also called “describing word” or “specifying word” (in Hindi “visheshan – विशेषण) . Like in Hindi, it agrees with the word it describes. It means that their ending changes according to the gender and number of that word.
Ex :
Un grand garçon. – A big boy.
Une grande fille. – A big girl.
De grands enfants. – Big kids.
Pour + d’infos :
https://grammar.collinsdictionary.com/french-easy-learning
French Language Online 