English adjectives form a large open category of words in English which, semantically, tend to denote properties such as size, colour, mood, quality, age, etc. with such members as other, big, new, good, different, Cuban, sure, important, and right.Aarts, Bas, et al. The Oxford Dictionary of English Grammar. 2nd ed., Oxford University Press, 2014, .Leech, Geoffrey N. A Glossary of English Grammar. Edinburgh UP, 2006. . Adjectives head adjective phrases, and the most typical members function as modifiers in noun phrases.Matthews, P. H. The Concise Oxford Dictionary of Linguistics. 3rd ed., Oxford University Press, 2014, . . Most adjectives either inflect for grade (e.g., big, bigger, biggest) or combine with more and most to form comparatives (e.g., more interesting) and superlatives (e.g., most interesting).Huddleston, Rodney, Geoffrey K. Pullum, and Brett Reynolds. A Student's Introduction to English Grammar. 2nd ed., Cambridge University Press, 2022. p.157. They are characteristically modifiable by very (e.g., very small). A large number of the most typical members combine with the suffix -ly to form adverbs (e.g., final + ly: finally). Most adjectives function as complements in verb phrases (e.g., It looks good), and some license complements of their own (e.g., happy that you're here).Huddleston, Rodney, and Geoffrey K. Pullum. The Cambridge Grammar of the English Language. Cambridge University Press, 2002. p. 57.
Syntax
Internal structure An adjective phrase (AdjP) is headed by an adjective and optionally takes dependents. AdjPs can take modifiers, which are usually pre-head adverb phrases (e.g., truly wonderful) or post-head preposition phrases (e.g., too big for you; afraid of the dark). The following tree diagram in the style of The Cambridge Grammar of the English Language shows the AdjP very happy to try, with the adverb very as a modifier and the clause to try as a complement.
Complements of adjectives English adjectives can take clauses, preposition phrases, and noun phrases as complements. Clause complements in adjective phrases can be either finite or nonfinite. Finite clause complements can be declarative (e.g., very pleased that I had bought his book) or interrogative (e.g., not sure whether I want to keep reading). Nonfinite clause complements can occur with a subject (e.g., happy for you to prove me wrong) or without a subject (e.g., eager to please). Adjectives that take preposition phrase complements license preposition phrases headed by fixed prepositions. For example, dependent takes preposition phrase complements headed only by on or upon. In some cases, a complement is obligatory; I'm loath to admit it is fine, but *I'm loath is incomplete. A small number of adjectives (due, like, near, unlike, and worth) can take noun phrases as complements.Aarts, Bas. Oxford Modern English Grammar. Oxford University Press, 2011. pp. 134–135. For example, worth can function as the head of an adjective phrase with a noun phrase complement (e.g., worth a second chance).
Modifiers of adjectives The prototypical pre-head modifiers of English adjectives are adverb phrases headed by degree adverbs, such as very and too.Lobeck, Anne, and Kristin Denham. Navigating English Grammar. Wiley-Blackwell, 2014. p. 154.Aarts, Bas. Oxford Modern English Grammar. Oxford University Press, 2011. pp. 136–138. For example, the adjective tall can be modified by the adverb phrase very. Less common pre-head modifiers in adjective phrases are noun phrases (e.g., six feet long), preposition phrases (e.g., by no means realistic), and determiner phrases (e.g., that small).
Preposition phrases function as post-head modifiers in English adjective phrases. In the adjective phrase foolish in the extreme, for example, the preposition phrase in the extreme functions as a modifier. Less commonly, certain adverbs (indeed and still) and one determiner (enough) can head phrases that function as post-head modifiers in adjective phrases (e.g., very harmful indeed, sweeter still, and fair enough).
Functions While adjectives themselves function only as heads in adjective phrases (an AdjP is often a head adjective with no dependents), adjective phrases function at the clause level as predicative complements and predicative adjuncts. At the phrase level, adjective phrases function as modifiers and predeterminatives in noun phrases and complements in some preposition phrases (e.g., they didn't look as good).Huddleston, Rodney D., Geoffrey K. Pullum, and Brett Reynolds. A Student's Introduction to English Grammar. 2nd ed., Cambridge University Press, 2022. pp.165–169.
Predicative complements At the clause level, adjective phrases commonly appear as predicative complements.Aarts, Bas. Oxford Modern English Grammar. Oxford University Press, 2011. pp. 97–100. A predicative complement is a constituent that ascribes a property to a predicand. For example, The dinner was lovely ascribes the property of being lovely to the dinner, the syntactic subject and semantic predicand. Predicative complements may be subject-related, as in the previous example, or object-related, the latter being licensed by complex transitive verbs such as feel and make, as in That made her hungry, where the property of being hungry is ascribed to the syntactic object and semantic predicand, her.
Predicative adjuncts Adjective phrases also function as predicative adjuncts in clause structure. Such adjective phrases can be integrated into the clause (e.g., Love dies young) or detached from the clause as a supplement (e.g., Happy to see her, I wept). Adjective phrases functioning as predicative adjuncts are typically interpreted with the subject of the main clause being the predicand of the adjunct (i.e., "I was happy to see her").Huddleston, Rodney, and Geoffrey K. Pullum. The Cambridge Grammar of the English Language. Cambridge University Press, 2002. pp. 528–531. When this is not the case, such supplements are often deprecated as dangling modifiers.
Modifiers within noun phrases Adjective phrases often function as pre-head (or attributive) modifiers in noun phrases, occurring after any determinative in the noun phrase (NP) (e.g., some nice folks). In some cases they are post-head (or postpositive) modifiers, with particular adjectives like galore (e.g., stories galore) or with certain compound heads like somebody (e.g., somebody special).Huddleston, Rodney, and Geoffrey K. Pullum. The Cambridge Grammar of the English Language. Cambridge University Press, 2002. pp. 550–553.
Predeterminatives within noun phrases Adjective phrases can function as predeterminatives under certain conditions. Specifically, they can do so only in noun phrases with a (or an) functioning as the determinative and only if the adjective phrase either has such or exclamative what as its head or begins with one of a small number of modifiers (i.e., as, how, so, this, that, or too). In the noun phrase such a difficult little devil, for example, the adjective phrase such functions as predeterminative. Similarly, in the clause how important a part is it?, the adjective phrase how important functions as predeterminative.
Complements within preposition phrases Adjective phrases can function as complements of preposition phrases.Aarts, Bas. Oxford Modern English Grammar. Oxford University Press, 2011. p. 153. In the clause the film characterized him as childish, for example, the adjective phrase childish functions as the complement of the preposition as.
Cases such as the poor and the French In cases such as the very poor and the French which denote a class, traditional grammars see the adjective as being "used as a noun".Eckersley, C. E., and J. M Eckersley. A Comprehensive English Grammar for Foreign Students. Longman, 1960. p. 58. However, poor cannot actually be a noun here for three reasons: very doesn't modify nouns, there is no possibility to pluralize poor (e.g., *three poors), and most determinatives are impossible (e.g., *a poor could not or *some poor did).
Other grammars see this as a case of ellipsis, where the head noun is simply left out and the AdjP is a regular modifier.Zwicky, Arnold M. “Heads.” Journal of Linguistics, vol. 21, no. 1, 1985, pp. 1–29. . In this view, the elided noun is something like one, and the very poor is an elided form of the very poor ones. Other accounts, such as one advanced by Bas Aarts, do not assume ellipsis but instead argue that phrases like these are best analyzed as noun phrases with an empty element functioning as the head, yielding an analysis like this: [NP the [AP veryAdv poorAdj] ∅N].Aarts, Bas. Syntactic Gradience: The Nature of Grammatical Indeterminacy. Oxford University Press, 2007. pp. 129–136.
The Cambridge Grammar of the English Language takes such instances to be fused modifier-heads. Under this analysis, adjective phrases may bear two functions at one time, fusing the functions of modifier and head in an NP where no head noun exists. In the noun phrase the very poor, the adjective poor is the fused modifier-head as shown in the tree diagram below.Huddleston, Rodney, and Geoffrey K. Pullum. The Cambridge Grammar of the English Language. Cambridge University Press, 2002. p. 332.
Types of adjectives
Non-attributive and non-predicative adjectives While most adjectives can function as both attributive modifier (e.g., a new job) and predicative complement (e.g., the job was new), some are limited to one or the other of these two functions.Garner, Bryan A. The Chicago Guide to English Grammar, Usage, and Punctuation. University of Chicago Press, 2016. pp. 58–60. For example, the adjective drunken cannot be used predicatively (a drunken fool vs *the fool was drunken), while the adjective awake has the opposite limitation (*an awake child vs the child is awake).
It is not only certain adjectives, but also certain constructions that are limited to one function or the other. For instance a nice hot bath is possible, as are the bath is hot and the bath is nice, but *the bath is nice hot is not.Matthews, P. H. The Positions of Adjectives in English. Oxford University Press, 2014. p. 136.
Linguist and historian Peter Matthews observes "that the attributive and predicative uses of adjectives have diverged" and continue to do so. For example, the sense of big in Well, that's big of you from the early 20th century is only possible as a predicative complement.
Gradable and non-gradable adjectives Most adjectives are gradable, but some are not (e.g., ancillary, bovine, municipal, pubic, first, etc.), or at least have particular senses in which they are not.Huddleston, Rodney, and Geoffrey K. Pullum. The Cambridge Grammar of the English Language. Cambridge University Press, 2002. p. 531–532. For example a very Canadian embassy can imply that the embassy has the stereotypically Canadian characteristics (politeness perhaps), but it cannot mean that the embassy represents Canada in the way that a Canadian embassy does.
Other types claimed in traditional grammars Many words that have been categorized by traditional grammars as types of adjectives are categorized as belonging to entirely different lexical categories by modern grammars, such as The Cambridge Grammar of the English Language. The types below are mostly of this kind. What these words have in common is, to put it in traditional terms, that they "qualify" nouns. In modern terms, they appear as pre-head dependents in noun phrases. Note that a word may be traditionally assigned to multiple types: for example whose is variously called a possessive adjective, an interrogative adjective, a pronominal adjective, and a relative adjective.
Quantitative adjectives