This is the 5076th most frequent Russian word.
модной
Fashionable.
Here, 'модной' is used as an adjective in the instrumental case form to describe 'одежду' (clothing), signifying it as having the quality of being fashionable.
Она всегда выбирает модной одежду для своих выходов.
She always chooses stylish clothing for her outings.
In this example, 'модной' describes a person in the role of a predicate, showing the state of being fashionable, applicable here in the feminine gender singular nominative case.
Каждому хочется быть модной в глазах окружающих.
Everyone wants to be fashionable in the eyes of others.
Here, 'модной' is used as a predicate adjective complementing 'кофточка' (blouse), indicating that the blouse possesses the quality of being fashionable.