In grammar
In linguistics, grammar is the set of structural rules that govern the composition of clauses, phrases, and words in any given natural language. The term refers also to the study of such rules, and this field includes morphology, syntax, and phonology, often complemented by phonetics, semantics,...

, an adjective is a 'describing' word; the main syntactic
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....

 role of which is to qualify
Grammatical modifier
In grammar, a modifier is an optional element in phrase structure or clause structure; the removal of the modifier typically doesn't affect the grammaticality of the sentence....

 a 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...

 or noun phrase
Noun phrase
In grammar, a noun phrase, nominal phrase, or nominal group is a phrase based on a noun, pronoun, or other noun-like word optionally accompanied by modifiers such as adjectives....

, giving more information about the object signified.

Adjectives are one of the traditional eight English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 parts of speech, though linguists
Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

 today distinguish adjectives from words such as determiners
Determiner (class)
A determiner is a noun-modifier that expresses the reference of a noun or noun-phrase in the context, rather than attributes expressed by adjectives...

 that were formerly considered to be adjectives. In this paragraph, "traditional" is an adjective, and in the preceding paragraph, "main" and "more" are.

Most but not all language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

s have adjectives.