General noun for interest, curiosity, or enthusiasm about something. Often used with ある, 持つ, 湧く, 深い, etc.
He is interested in Japanese history.
その話を聞いて、急に興味が湧いた。
Hearing that story, I suddenly became interested.
I'm interested in history.
The child showed interest in the new toy.
After watching that movie, I became interested in Japanese culture.
He quickly lost interest.
My interest in science deepens every year.
uninteresting; dampening the mood; spoiling the fun
uninteresting; of little interest