adjectival noun

plural adjectival nouns

1. human sciencesA noun used as an adjective.

   Near-synonyms: attributive noun, noun adjunct (broadly synonymous)

   Synonyms: attributive noun, noun adjunct[Appendix:Glossary

2. A specific part of speech, categorized in Japanese as 形容動詞 (keiyō dōshi). Some of these words can be used as regular nouns, and all can be used as adjectives when followed by the postfix な (na), in contrast to Japanese common adjectives, 形容詞 (keiyōshi).
3. Nouns that have the form of adjectives (often originally adjectives used as nouns).

   Adjectival nouns are simply identical in form to adjectives of a particular gender and decline accordingly.

   2005, James D. Naughton, Czech: An Essential Grammar, London, New York: Routledge, →ISBN, page 45

4. sometimesA nominalized adjective.