Choose the perfect synonym or antonym for the word

Mainstream

/ˈmeɪnstriːm/

Related to the common trends, ideas, or attitudes accepted by a majority of people or groups.

Synonyms:

Eco-friendly products are becoming mainstream now.

His views are too conventional for the mainstream audience.

She aims to blend avant-garde with mainstream appeal.

First known use in 1831, derived from main meaning principal or chief, and stream, suggesting a continuous flow of ideas or tendencies.

21 mentions per 1 million words

Often

Hint: Frequency according to COCA