In linguistics, a nominal is a part of speech in some languages that shares features with noun

Noun

In linguistics, a noun is a member of a large, open lexical category whose members can occur as the main word in the subject of a clause, the object of a verb, or the object of a preposition .Lexical categories are defined in terms of how their members combine with other kinds of...

s and adjective

Adjective

In grammar, an adjective is a 'describing' word; the main syntactic role of which is to qualify a noun or noun phrase, giving more information about the object signified....

s.

Examples

Nominals are a common feature of Indigenous Australian languages, many of which do not categorically differentiate nouns from adjectives.

Some features of nominals in some Australian languages include:

• the ability to take grammatical case
  Grammatical case
  In grammar, the case of a noun or pronoun is an inflectional form that indicates its grammatical function in a phrase, clause, or sentence. For example, a pronoun may play the role of subject , of direct object , or of possessor...
  
   marking,
• the ability to function substantively (head a noun phrase), and
• the ability to function predicatively
  Predicative (adjectival or nominal)
  In grammar, a predicative is an element of the predicate of a sentence that supplements the subject or object by means of the verb. A predicative may be nominal or adjectival . If the complement after a linking verb is a noun or a pronoun, it is called a predicate nominative...
  
   (modify another nominal).

Japanese

In Japanese, 形容動詞, keiyō-dōshi (literally "adjectival verbs") can be analyzed as nominals – see adjectival noun (Japanese)