Nouning

[Zipporah Schumaker]

The use of another part of speech as a noun.

[Gregory]

The act of [changing] [words] that are not [typically] nouns into nouns.

[Britney]

The process of turning a word into a noun. [Technically], the process is different than gerunds because the results are slang, [not real] words. Its also possible to noun things that are already nouns.
See also [verbing]