This is the 9713th most frequent Japanese word.
茶色い
Brown.
Here, '茶色い' is used as an adjective describing the color of the hat.
その茶色い帽子をかぶってください。
Please wear that brown hat.
In this sentence, '茶色い' modifies the noun 'dog', specifying its color.
茶色い犬が公園で遊んでいます。
A brown dog is playing in the park.
'茶色い' serves as an adjective describing the color of the bag.