Complement in Grammar

The word or words complete a predicate in a sentence

Complements in English grammar
In sentence (1), treasurer functions as a subject complement. In sentence (2), treasurer functions as an object complement.

In grammar, a complement is a word or word group that completes the predicate in a sentence. In contrast to modifiers, which are optional, complements are required to complete the meaning of a sentence or a part of a sentence.

Below you'll find discussions of two common types of complements: subject complements (which follow the verb be and other linking verbs) and object complements (which follow a direct object). As David Crystal has observed, in the "Dictionary of Linguistics and Phonetics":

"[T]he domain of complementation remains an unclear area in linguistic analysis, and there are several unresolved issues."

Subject Complements Examples

These are examples of subject complements. In this and the subsequent sections, the complement or complements are listed in italics.

  • My uniform is torn and dirty.
  • My uniform is a T-shirt and jeans.
  • "Imagination is the one weapon in the war against reality. – Jules de Gaultier
  • "Love is an exploding cigar we willingly smoke."
    – Lynda Barry

Object Complements Examples

  • Jimmy's teacher called him a troublemaker.
  • The teacher's remark made me angry.
  • "The widow she cried over me, and called me a poor lost lamb, and she called me a lot of other names, too."
    – Mark Twain, "Adventures of Huckleberry Finn"

Subject Complements Explanations

"Subject complements rename or describe the subjects of sentences. In other words, they complement the subjects.
"Many of these complements are nouns, pronouns, or other nominals that rename or provide additional information about the subject of the sentence. They always follow linking verbs. A less contemporary term for a noun, pronoun, or other nominal used as a subject complement is predicate nominative.
  • He is the boss.
  • Nancy is the winner.
  • This is she.
  • My friends are they.
"In the first example, the subject complement boss explains the subject he. It tells what he is. In the second example, the subject complement winner explains the subject Nancy. It tells what Nancy is. In the third example, the subject complement she renames the subject this. It tells who this is. In the final example, the subject complement they identifies the subject friends. It tells who the friends are.
"Other subject complements are adjectives that modify the subjects of sentences. They also follow linking verbs. A less contemporary term for an adjective used as a subject complement is predicate adjective.
  • My coworkers are friendly.
  • This story is exciting.
"In the first example, the subject complement friendly modifies the subject coworkers. In the second example, the subject complement exciting modifies the subject story."

– Michael Strumpf and Auriel Douglas, "The Grammar Bible." Henry Holt, 2004

Object Complements

"An object complement always follows the direct object and either renames or describes the direct object. Consider this sentence:
  • She named the baby Bruce.
"The verb is named. To find the subject, ask, 'Who or what named?' The answer is she, so she is the subject. Now ask, 'Whom or what did she name?' She named the baby, so baby is the direct object. Any word following the direct object that renames or describes the direct object is an object complement. She named the baby Bruce, so Bruce is the object complement."

– Barbara Goldstein, Jack Waugh, and Karen Linsky, "Grammar to Go: How It Works and How to Use It," 4th ed. Wadsworth, 2013

"The object complement characterizes the object in the same way as the subject complement characterizes the subject: it identifies, describes, or locates the object (as in We chose Bill as group leader, We consider him a fool, She laid the baby in the crib), expressing either its current state or resulting state (as in They found him in the kitchen vs. She made him angry). It is not possible to delete the object complement without either radically changing the meaning of the sentence (e.g. She called him an idiot - She called him) or making the sentence ungrammatical (e.g. He locked his keys in his office - *He locked his keys). Note that be or some other copula verb can often be inserted between the direct object and the object complement (e.g. I consider him to be a fool, We chose Bill to be group leader, They found him to be in the kitchen)."

– Laurel J. Brinton and Donna M. Brinton, The Linguistic Structure of Modern English. John Benjamins, 2010

Multiple Meanings of "Complement"

"Complement is one of the most confusing terms in scientific grammar. Even in one grammar, that of Quirk et al. (1985), we can find it being used in two ways:
a) as one of the five so-called 'clause elements' (1985: 728), (alongside subject, verb, object and adverbial):
(20) My glass is empty. (subject complement)
(21) We find them very pleasant. (object complement)
b) as a part of a prepositional phrase, the part that follows the preposition (1985: 657):
(22) on the table
"In other grammars, this second meaning is extended to other phrases....It therefore appears to have very broad reference, to anything that is needed to complete the meaning of some other linguistic unit...
"These two basic meanings of complement are neatly discussed in Swan [see below]."

– Roger Berry, "Terminology in English Language Teaching: Nature and Use." Peter Lang, 2010)

"The word 'complement' is also used in a wider sense. We often need to add something to a verb, noun, or adjective to complete its meaning. If somebody says I want, we expect to hear what he or she wants; the words the need obviously don't make sense alone; after hearing I'm interested, we may need to be told what the speaker is interested in. Words and expressions which 'complete' the meaning of a verb, noun, or adjective are also called 'complements.'
"Many verbs can be followed by noun complements or -ing forms with no preposition ('direct objects'). But nouns and adjectives normally need prepositions to join them to noun or -ing form complements."

– Michael Swan, "Practical English Usage." Oxford University Press, 1995)

  • I want a drink, and then I want to go home.
  • Does she understand the need for secrecy?
  • I'm interested in learning to fly.

From the Latin, "to fill out"

Pronunciation: KOM-pli-ment

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Nordquist, Richard. "Complement in Grammar." ThoughtCo, Apr. 5, 2023, Nordquist, Richard. (2023, April 5). Complement in Grammar. Retrieved from Nordquist, Richard. "Complement in Grammar." ThoughtCo. (accessed June 7, 2023).