What is a noun for the word dark?

There isn't one perfect noun for "dark" that captures all its meanings. However, depending on the context, you can use:

For literal darkness:

* Darkness: This is the most straightforward option.

* Gloom: Implies a heavy, oppressive darkness.

* Shade: Can refer to a lighter form of darkness, like the shadow of a tree.

* Obscurity: Refers to a state of being hidden or unknown.

* Night: Specifically refers to the period of darkness after sunset.

For figurative darkness:

* Mystery: Can refer to something unknown or hidden.

* Ignorance: Refers to a lack of knowledge or understanding.

* Despair: Can refer to a state of hopelessness or sadness.

* Evil: Can refer to something morally wrong or harmful.

The best choice will depend on the specific meaning you want to convey.