This is the 960th most frequent Hindi word.
adj
The term "adj" is not a Hindi word; it is an abbreviation for "adjective" in English.
Here, the word 'अच्छी' functions as an adjective to describe the noun 'पुस्तक'.
यह एक अच्छी पुस्तक है।
This is a good book.
Here, the word 'बड़ा' operates as an adjective providing additional information about 'घर'.
उसने एक बड़ा घर खरीदा।
He/She bought a big house.
In this sentence, 'छोटा' is an adjective modifying the noun 'केक', explaining its size.