What does complementizer mean?
A complementizer is a grammatical word that introduces a subordinate clause acting as the complement of a verb, noun, or adjective within a sentence. In English, the classic example is 'that' in constructions such as 'She said that she would come,' where it marks the beginning of the embedded clause. Linguists also use the term more abstractly to refer to the syntactic category (C) that occupies the head position of a clause, whether or not any visible word fills it — a silent, or null, complementizer is posited whenever a clause appears without an introductory word. The concept belongs to formal syntax and generative grammar, so it appears mainly in linguistics research, textbooks, and advanced language teaching rather than everyday conversation. Understanding complementizers illuminates how languages package whole clauses as objects: many languages possess their own distinctive complementizing words, and comparing them reveals deep patterns in how humans embed one thought inside another.
nounIn linguistics, a word — most typically 'that' in English — which introduces a subordinate clause functioning as the complement of a verb, noun, or adjective. The term also denotes the syntactic category (abbreviated C) that heads such clause-introducing elements.
- A word, especially 'that', that introduces a subordinate clause serving as the complement of a verb, noun, or adjective.
- The abstract syntactic category or head position (C) in generative grammar that hosts such clause-introducing elements.
"In the sentence 'She said that she was tired,' the word 'that' serves as a complementizer linking the main clause to the subordinate one."
"Linguists note that the complementizer 'that' can often be omitted in informal English: 'I know (that) you're busy.'"
"The analysis treats every finite clause as containing a complementizer position, even when no overt word fills it."
Regular plural; used freely in linguistics literature when comparing clause-introducing elements within or across languages.
"English draws its complementizers from a small set, including 'that', 'whether', and 'if'."
Every English sentence like 'I think THAT it works' hides a tiny grammatical workhorse called a complementizer — and dropping it is one of the subtlest markers of casual speech.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of complementizer
The word combines the noun 'complement' with the agentive suffix '-izer', literally 'something that complements'. 'Complement' derives from Latin 'complementum', meaning 'that which fills up or completes', from 'complere' ('to fill up'), itself formed from the prefix 'com-' ('with, together') and 'plere' ('to fill'). The linguistic term arose in twentieth-century generative grammar, when syntacticians needed a name for the class of clause-introducing elements, and it has cognates in the wider family of 'comple-/plet-' words such as 'complete' and 'completion'.
How complementizer is actually used
Strictly a technical term of linguistics; rarely encountered outside academic writing on syntax, grammar pedagogy, or linguistics textbooks. In British usage the final vowel may reduce slightly, but stress remains on the first syllable. The plural 'complementizers' is standard when discussing multiple such elements across languages.
Easily confused with complementizer
A complementizer is a grammatical element introducing a subordinate clause; a compliment is a flattering remark — the two share only an etymological root and differ entirely in meaning.