[[An adnominal modifier is a non-°affixal expression that occurs in a °nominal and that provides further information beyond the °noun.]]
In the Grammaticon definition, "modifier" is restricted to adnominal use, so "adnominal modifier" could be shortened to "modifier". However, since "modification" is often used more widely in the literature (including adverbials in clauses), the tautological term "adnominal modifier" is used here.
"Attributive" is an older synonym of "adnominal" that is still very widely used.
attributive phrase (CXN) = a construction that performs the act of modification. Example: in a very slow truck, the attributive phrase very slow modifies the truck with respect to its speed. The head of an attributive phrase is a modifier. The prototypical attributive phrase is an adjectival phrase. (Sections 2.2.2, 4.1.1) ❡ modifier (CXN) = the head of an attributive phrase. Example: in nearly fifty trees, fifty is a modifier. A prototypical modifier, a property concept, is an adjective. (Section 2.2.4)
"Pronominal demonstratives are independent pronouns in argument position of verbs and adpositions. They are often formally distinguished from adnominal demonstratives, which accompany a cooccurring noun. For instance, French uses the demonstratives celui, celle, ceux, and celles as independent pronouns and ce, cette, and ces as modifiers of a subsequent noun." (Diessel 1999: 4)