Adnominal adjective agreement is when qualitative adjectives in an attributive phrase are required to be marked for the same grammatical features (specifically, class (gender), number, and/or case) as the noun they modify. Prototypically, qualitative adjectives describing size, shape, and color should be examined with the attributive phrase functioning as an adverbial.[1]

Types:

NoAgrCat: Adjective agreement with the noun is not possible, because the features class (gender), number, and case do not exist.

NoAgr: At least one of the features of class (gender), number, and case exists in the language, but adnominal (attributive) constructions do not show agreement for any features between nouns and adjectives.

NoAdjAgr: Although other elements in the noun phrase can display agreement with the noun[2], adjectives cannot.

AdjAgr: Adnominal adjectives show agreement for all grammatical categories that are marked for agreement on nouns.

AdjNumAgr: Adnominal adjectives display agreement with the noun only in terms of number, although the noun is also marked in terms of other features.[3]

AdjCaseAgr: Adnominal adjectives display agreement with the noun only in terms of case, although the noun is also marked in terms of other features.

AdjClassAgr: Adnominal adjectives display agreement with the noun only in terms of gender, although the noun is also marked in terms of other features.

AdjNumAdjCaseAgr: Adnominal adjectives display agreement with the noun only in terms of case and number, although the noun is also marked in terms of other features.[4]

[1] When a language displays more than one type, multiple values can be listed. If one type is dominant, a slash (/) can separate the two values, with the dominant value appearing first; if neither is dominant, they are listed with an ampersand (&) separating the two. For example, AdjAgr&AdjNumAgr denotes a language in which some adjectives show agreement in terms of all possible features and others show agreement in terms of number, and each type occurs with the same frequency. AdjAgr/AdjNumAgr describes a language in which most adjectives show agreement in terms of all possible features, while a limited set agree only in terms of number.

[2] Agreement refers to grammatical gender, number, and/or case. Non-adjectival forms of agreement may include adnominal demonstratives.

[3] This value includes languages in which the form of an adjective is modified based on the grammatical case of the noun it modifies, despite not being itself marked for case.

[4] Other parameter values can be created based on this pattern. For example, the value AdjNumAdjClassAgr would indicate that adjectives in the language agree only in terms of number and gender, not case.