noun
blue film; pornographic movie
A slightly dated term for a pornographic film, often with a connotation of being screened secretly or underground. In modern Japanese, アダルトビデオ (AV) is more common for commercial adult videos.
昔はブルーフィルムをこっそり見るのが流行っていた。
Back in the day, it was popular to secretly watch blue films.
この映画館では深夜にブルーフィルムを
Apparently this theater used to screen blue films late at night.