In grammar, a complement is a word or group that completes the meaning of a verb, noun, or adjective. It fills in missing information so a sentence feels complete and makes sense.
Complements are essential in constructing clear, accurate statements. Without them, many sentences would lack necessary context. For example, "She is happy" is incomplete without "happy," which acts as a subject complement. The adjective "happy" completes the meaning of the linking verb "is."
According to the Oxford Dictionary of English Grammar, complements are "elements required to complete the syntactic structure of a clause." They differ from modifiers, which add detail but aren't necessary for grammatical completeness. A complement is not optional-it's required for the sentence to be fully formed.
Complements appear in several roles within a sentence. The most common are subject complements, object complements, and verb complements. Each serves a distinct purpose in completing the action or state described by the verb.
Subject complements follow linking verbs such as "be," "seem," "become," or "appear." They describe or rename the subject. In "The winner became champion," "champion" is a subject complement because it identifies who the winner became. This differs from an object complement, which describes the direct object.
Object complements occur after a direct object and describe or rename it. In "They elected her president," "president" is an object complement. It completes the meaning of the verb "elected" by specifying what she was elected to. Without "president," the sentence would be unclear.
Verb complements are less common but still important. Some verbs require specific complements to make sense. For example, "I expect him to arrive early." Here, "to arrive early" is a verb complement. It completes the meaning of "expect." The infinitive phrase functions as a complement, not a modifier.
Complements fall into three main categories based on their position and function. Each type plays a unique role in sentence construction.
| Type | Function | Example | Source |
|---|---|---|---|
| Subject complement | Describes or renames the subject after a linking verb | "He seems tired." | Oxford Dictionary of English Grammar |
| Object complement | Describes or renames the direct object | "They named the dog Max." | Cambridge Grammar of the English Language |
| Verb complement | Completes the meaning of a transitive verb | "She hopes to win." | Cambridge Grammar of the English Language |
A common mistake is confusing complements with adverbial modifiers. For example, in "She arrived late," "late" is an adverb modifying "arrived." It tells when or how, but it doesn't complete the meaning of the verb. In contrast, "She arrived home" uses "home" as a complement-it completes the meaning of "arrived" by indicating destination.
Another subtle distinction: not all phrases following a verb are complements. Only those that are semantically required count. In "I saw the movie," "the movie" is a direct object, not a complement. But in "I consider the movie excellent," "excellent" is a subject complement because it describes the subject "the movie" after the linking verb "consider."
Complements appear frequently in both spoken and written English. Misunderstanding them leads to awkward phrasing or ambiguous meaning.
Consider the sentence: "The teacher called the student lazy." "Lazy" is an object complement. It describes the direct object "student." If you remove "lazy," the sentence becomes "The teacher called the student," which lacks clarity. The complement completes the meaning of the verb "called."
Non-native speakers often confuse complements with indirect objects. In "She gave her friend a book," "her friend" is the indirect object. "A book" is the direct object. Neither is a complement. But in "She made her friend happy," "happy" is a subject complement. It describes the result of the action. The verb "made" requires a complement to express the outcome.
A lesser-known fact: some verbs take only certain types of complements. For example, "promise" takes an infinitive complement: "She promised to come." You cannot say "She promised coming" and be correct. The verb "promise" demands a to-infinitive. This is a syntactic requirement, not a stylistic choice.
I once observed a student write: "The project was completed by the team." That's correct. But then they added: "The team was very proud." "Very proud" is a subject complement. It completes the meaning of the linking verb "was." Removing it leaves the sentence vague: "The team was" - what? The complement supplies the missing information.
Knowing the meaning of complement helps improve writing clarity, avoid ambiguity, and improve comprehension. It's especially useful in editing, translation, and academic writing.
For example, in legal documents, precision matters. A sentence like "The contract was deemed valid" relies on "valid" as a subject complement. Changing it to "The contract was deemed validly" introduces a misplaced adverb and distorts meaning. The complement "valid" is necessary for grammatical correctness.
When learning English, recognizing complements helps distinguish between acceptable and ungrammatical structures. A student who knows that "became" requires a complement will avoid errors like "He became smart" (incorrect) versus "He became smart" (correct only if "smart" is used as a subject complement).
Understanding complement also aids in parsing complex sentences. In "The results proved disappointing," "disappointing" is a subject complement. It completes the meaning of "proved." Without it, the sentence lacks closure. The complement provides the necessary semantic completion.
The meaning of complement is not just theoretical-it shapes how we understand and construct language. Recognizing it improves accuracy in both speaking and writing.