General:
* Dullness: This is the most direct and common option, meaning a lack of excitement or interest.
* Tedium: This refers to a feeling of weariness or boredom, often caused by something repetitive or monotonous.
* Monotony: This describes a lack of variety or change, leading to boredom.
More specific:
* Blandness: This describes a lack of flavor or excitement, often used for food or entertainment.
* Banality: This refers to something common, ordinary, and lacking in originality, often leading to boredom.
* Tiresomeness: This refers to something that makes you tired or weary, potentially causing boredom.
The best noun to use will depend on the specific context and what you want to emphasize. For example, if you're talking about a boring movie, "dullness" or "blandness" might be appropriate. If you're talking about a boring job, "tedium" or "monotony" might be better.