Adjective Complements

What is an adjective complement?

An adjective complement (also called an adjective phrase complement) is a phrase or clause that provides information necessary to complete an adjective phrase’s meaning. They are most often used with predicative adjectives (adjectives that follow linking verbs to describe the subject of the clause).

Note that some grammar guides refer to predicative adjectives as being synonymous with adjective complements. In this guide, however, an adjective complement refers to that which completes the meaning of an adjective, while a predicative adjective (a kind of subject complement) completes the meaning of a subject.

Types of Adjective Complements

Adjective complements can be prepositional phrases, infinitive phrases, or noun clauses.

Prepositional Phrases

A prepositional phrase is comprised of a preposition immediately followed by a noun, pronoun, noun phrase, pronoun phrase, or noun clause. Here are some examples of prepositional phrases acting as adjective complements:

• “I am perfectly content on my own.” (On my own is the complement of the adjective content.)
• “He felt alone in the world.” (In the world is the complement of the adjective alone.)
• “They seem a little concerned about the direction we’re taking.” (About the direction we’re taking is the complement of the adjective concerned.)
• “She is skilled at archery.” (At archery is the complement of the adjective skilled.)
• “The bosses are pleased with your progress.” (With your progress is the complement of the adjective pleased.)

Infinitive Phrases

Infinitive phrases are formed from full infinitive verbs (to + the base form of the verb) plus any additional objects or modifiers of the verb. (Be careful not to confuse infinitive phrases with prepositional phrases beginning with to.)

For example:

• “I’m very happy to know you!” (To know you is the complement of the adjective happy.)
• “We’re just glad to be of service.” (To be of service is the complement of the adjective glad.)
• “They felt relieved to return home.” (To return home is the complement of the adjective relieved.)
• “The crowd seemed impatient to begin.” (To begin is the complement of the adjective impatient.)

Noun Clauses

A noun clause is a dependent clause that is able to function grammatically like a noun. Noun clauses begin with the words that, how, if, and the “wh-” words—what, whatever, where, wherever, when, whenever, why, which, whichever, who, whom, whoever, whomever, whether, and whatever.

• “We were a little curious why they decided to leave.” (Why they decided to leave is the complement of the adjective curious.)
• “I’m thrilled that you are coming to visit!” (That you are coming to visit is the complement of the adjective thrilled.)
• “The boss is certain who will lead the next project.” (Who will lead the next project is the complement of the adjective certain.)
• “They’re somewhat unsure whether this is the right decision.” (Whether this is the right decision is the complement of the adjective unsure.)

Modifiers vs. Complements

Adjective complements are similar to but distinct from modifiers of adjectives. Both function adverbially, but while adjective modifiers describe or elaborate upon an adjective’s meaning, adjective complements work with adjectives to complete their meaning. The meaning of the sentence will not change if the modifier is taken out, whereas some information will be lost or altered if the complement is removed.

• “I am perfectly content on my own.” (Perfectly is an adverb that modifies the adjective content, while on my own is a prepositional phrase that complements it.)
• “They seem a little concerned about the direction we’re taking.” (A little is an adverbial phrase that modifies the adjective concerned, while about the direction we’re taking is a prepositional phrase that complements it.)
• “I’m very happy to know you!” (Very is an adverb that modifies the adjective happy, while to know you is an infinitive phrase that complements it.)
• “We’re just glad to be of service.” (Just is an adverb that modifies the adjective glad, while to be of service is an infinitive phrase that complements it.)
• “We were a little curious why they decided to leave.” (A little is an adverbial phrase that modifies the adjective curious, while why they decided to leave is a noun clause that complements it.)
• “They’re somewhat unsure whether this is the right decision.” (Somewhat is an adverbial phrase that modifies the adjective unsure, while whether this is the right decision is a noun clause that complements it.)