Here are some ways to describe something as boring:
* Lack of excitement: "The movie was so boring, I almost fell asleep."
* Monotonous and repetitive: "The work was boring, doing the same thing every day."
* Lack of stimulation: "The lecture was incredibly boring, I couldn't focus at all."
* Predictable and uninspiring: "The conversation was boring, we just talked about the weather."
* Lack of novelty or freshness: "The food was boring, just the same old things."
The opposite of boring is exciting, stimulating, engaging, interesting, and novel.