What is deep's noun?

Answer 1

The word deep is an adjective, an adverb, and a noun.

The noun deep is a word for the deep of the ocean or the extent of time, space, or emotion; a common, abstract, mass (uncountable) noun, a word for a concept.

Example uses:

Noun: The creature slipped into the deep and was not seen again.

Adjective: We aren't allowed at the deep end of the pool.

Adverb: We trekked deepInto the Woods but couldn't find the species we sought.

The abstract noun form for the adjective deep is deepness.

Another abstract noun form is depth.

Answer 2

The noun form of "deep" is typically "depth."