Yeah! It is. It is called an adjectival noun. It simply refers to an adjective that functions as a noun.
Adjectives are often used as nouns:
1/In the examples illustrated bellow, the adjectives acting as nouns form a part of the subject.
- The hardworking are not snob
- The poor are underestimated.
‘the hardworking’ and ‘the poor’ are adjectives acting as nouns.
The full noun phrases could be:
- The hardworking (people) are not snob
- The poor (students) are underestimated.
2/Furthermore, they can function as objects:
- She is a fan of the dummy.
- He has an eye for the aristocrats.
‘the dummy’ and ‘the aristocrats’ are adjectives acting as nouns. The complete sentences could be:
- She is a fan of the dummy(minds).
- He has an eye for the aristocrats (ladies).