There are several features that are often taken to be characteristic of adjectives, but which are nevertheless not sufficient to fully delimit the set of adjectives. For example, many adjectives can be used in both prenominal attributive and clause-final predicative positions, as illustrated for aardignice in (1a) and (1a'), respectively. However, since this does not hold for all adjectives, the ability to be used in these positions is not a necessary condition for classifying a lexical item as an adjective: deksels and onwel in the (b) and (c)-examples are usually considered adjectives, despite the fact that the former can only be used in attributive position and the latter can only be used in predicative position.

Two other features are often considered characteristic of the class of adjectives: modification by an adverbial phrase of degree such as zeervery or vrijrather, as in (2a), and comparative/superlative formation, as in (2b&c). The primed examples show, however, that these features again single out only a subset of adjectives, namely the set of so-called gradable adjectives.

Since the properties discussed above characterize only subsets of adjectives, perhaps the best way to characterize this category is to compare it to the categories of verbs and nouns.

Verbs and (at least a subset of) adjectives both have the property that they can be predicated of a noun phrase in the clause. The most conspicuous difference between the two categories is that only the former can be inflected with a tense morpheme: finite verbs can express present or past tense; cf. Ik wandel/wandeldeI walk/walked. If adjectives are predicated of the subject of the clause, they are not inflected in Dutch and a copula must be inserted to express tense; cf. Ik ben/was ziekI am/was ill. Furthermore, finite verbs agree in number and person with the subject of the clause, whereas Dutch predicatively used adjectives never show agreement when they are predicated of the subject of the clause.

Nouns are typically used to refer to an entity (or set of entities) in the domain of discourse. Because of this property, noun phrases can refer to participants in an eventuality, and thus have the syntactic function of subject or direct/indirect object of a clause. Adjectives usually do not perform these syntactic functions (but see Section 28.5.3 for some exceptional cases), which is especially true when the clause is headed by a main verb with descriptive content. This becomes quite clear when we compare the examples in (3). The noun phrase drie zeldzame vogels in (3a) clearly functions as direct object: it is clearly referential and can be promoted to subject in a passive construction (cf. Er werden drie zeldzame vogels gezienThree rare birds were seen). The adjective phrase erg bleek does not function as direct object: it does not refer to entities but to a property of the subject of the clause, and passivization is impossible (cf. *Er werd erg bleek gezien).

Despite the fact that it is not easy to characterize the class of adjectives, we will try to discuss some of the prominent properties of this word class in this chapter: Section 23.1 begins with a brief overview of the syntactic uses of adjectives, Section 23.2 discusses the inflectional properties of attributively used adjectives, and Section 23.3 concludes with a semantic classification of adjectives, which at least partly coincides with classifications that can be made on syntactic or morphological grounds.