The word 'noun' is a noun, a thing.
Her is a possessive adjective, neither a noun, nor a verb.
"Their" is neither a noun nor a verb; it is a pronoun in its possessive case.
The present participle of a verb, the -ing word, is also used as a noun called a gerund. The present participle can also be an adjective. Examples: Verb: We were swimming at the community center....