Adjective

An adjective, in grammar, is a word whose main syntactic role is to modify a noun or pronoun (called the adjective's head), giving more information about to what the noun or pronoun refers. Some examples can be seen in the box to the right. Collectively, adjectives form one of the traditional eight parts of speech, though linguists today distinguish adjectives from words such as determiners that used to be considered adjectives but that are now recognized to be different. It derives from the Latin words ad and iacere (Latin words that start with an I change to a J in English); literally, to throw to.

Not all languages have adjectives, but most, including English, do. (English adjectives include big, old, and tired, among many others.) Those that do not typically use words of another part of speech, often verbs, to serve the same semantic function; for example, such a language might have a verb that means "to be big", and would use a construction analogous to "big-being house" to express what English expresses as "big house". Even in languages that do have adjectives, one language's adjective might not be another's; for example, where English has "to be hungry" (hungry being an adjective), French has "avoir faim" (literally "to have hunger"), and where Hebrew has the adjective "זקוק" (zaqūq, roughly "in need of"), English uses the verb "to need".

In most languages with adjectives, they form an open class of words; that is, it is relatively common for new adjectives to be formed via such processes as derivation.

Classes of adjectives

There are 6 classes of adjectives in the English language:

1. Numeric: six, three hundred
2. Quantitative: more, all, some, half, more than enough
3. Qualitative: Relates to colour, size, smell etc.
4. Possessive: my, his, their, your
5. Interrogative: which, whose, what
6. Demonstrative: this, that, those, these

Adjectives also have different levels of intensity (See, superlative, comparative, nominative)

Adjectives and adverbs

Many languages, including English, distinguish between adjectives, which modify nouns and pronouns, and adverbs, which modify verbs, adjectives, and other adverbs. Not all languages have exactly this distinction, however, and in many languages (including English) there are words that can function as both. For example, English fast is an adjective in "a fast car" (where it modifies the noun car), but an adverb in "he drove fast" (where it modifies the verb drove).

Adjectival phrases

An adjective acts as the head of an adjectival phrase. In the simplest case, an adjectival phrase consists solely of the adjective; more complex adjectival phrases may contain one or more adverbs modifying the adjective ("very strong"), or one or more complements ("worth several dollars", "full of toys", "eager to please). In English, attributive adjectival phrases that include complements typically follow their subject ("an evildoer devoid of redeeming qualities").

Determiners

Linguists today distinguish determiners from adjectives, considering them to be two separate parts of speech (or lexical categories), but traditionally, determiners were considered adjectives in some of their uses. (In English dictionaries, which typically still do not treat determiners as their own part of speech, determiners are often recognizable by being listed both as adjectives and as pronouns.) Determiners are words that express the reference of a noun in the context, generally indicating definiteness (as in a vs. the), quantity (as in one vs. some vs. many), or another such property.

Attributive, predicative, absolute, and substantive adjectives

A given occurrence of an adjective can generally be classified into one of four kinds of uses:

• Attributive adjectives are part of the noun phrase headed by the noun they modify; for example, happy is an attributive adjective in "happy kids". In some languages, attributive adjectives precede their nouns; in others, they follow their nouns; and in yet others, it depends on the adjective, or on the exact relationship of the adjective to the noun. In English, attributive adjectives usually precede their nouns in simple phrases, but often follow their nouns when the adjective is modified or qualified by a phrase acting as an adverb. For example: "I saw three happy kids", and "I saw three kids happy enough to jump up and down with glee".
• Predicative adjectives are linked via a copula or other linking mechanism to the noun or pronoun they modify; for example, happy is a predicate adjective in "they are happy" and in "that made me happy". (See also: predicative, subject complement.)
• Absolute adjectives do not belong to a larger construction (aside from a larger adjective phrase), and typically modify either the subject of a sentence or whatever noun or pronoun they are closest to; for example, happy is an absolute adjective in "The boy, happy with his lollipop, did not look where he was going."
• Substantive adjectives act almost as nouns. One way this can happen is if a noun is elided and an attributive adjective is left behind. In the sentence, "I read two books to them; he preferred the sad book, but she preferred the happy," happy is a substantive adjective, short for "happy one" or "happy book". Another way this can happen is in phrases like "out with the old, in with the new", where "the old" means, "that which is old" or "all that is old", and similarly with "the new". In such cases, the adjective functions either as a mass noun (as in the preceding example) or as a plural count noun, as in "The meek shall inherit the Earth", where "the meek" means "those who are meek" or "all who are meek".

Adjective order

In many languages, attributive adjectives usually occur in a specific order; for example, in English, adjectives pertaining to size generally precede adjectives pertaining to age ("little old", not "old little"), which in turn generally precede adjectives pertaining to color ("old green", not "green old"). This order may be more rigid in some languages than others; in some, it may only be a default (unmarked) word order, with other orders being permissible to shift the emphasis.

Comparison of adjectives

In many languages, adjectives can be compared. In English, for example, we can say that a car is big, that it is bigger than another is, or that it is the biggest car of all. Not all adjectives lend themselves to comparison, however; for example, the English adjective even, in the sense of "being a multiple of two", is not considered comparable, in that it does not make sense to describe one integer as "more even" than another.

Among languages that allow adjectives to be compared in this way, different approaches are used. Indeed, even within English, two different approaches are used: the suffixes -er and -est, and the words more and most. (In English, the general tendency is for shorter adjectives and adjectives from Anglo-Saxon to use -er and -est, and for longer adjectives and adjectives from French, Latin, Greek, and other languages to use more and most.) By either approach, English adjectives therefore have positive forms (big), comparative forms (bigger), and superlative forms (biggest); many languages do not distinguish comparative from superlative forms, however.

Restrictiveness

Attributive adjectives, and other noun modifiers, may be used either restrictively (helping to identify the noun's referent, hence "restricting" its reference), or non-restrictively (helping to describe an already-identified noun). In some languages, such as Spanish, restrictiveness is consistently marked; for example, Spanish la tarea difícil means "the difficult task" in the sense of "the task that is difficult" (restrictive), while la difícil tarea means "the difficult task" in the sense of "the task, which is difficult" (non-restrictive). In English, restrictiveness is not marked on adjectives, but is marked on relative clauses (the difference between "the man who recognized me was there" and "the man, who recognized me, was there" being one of restrictiveness).