complement
gb/kˈɑmpləmənt/ us/kˈɑmpləmənt/
B2
English
~ 8600
Senses
0 senses
Noun
B2
entity
1
something that completes or pairs well
Something that makes another thing complete or better, or goes very well with it.
Usage pattern:
[something] is a complement to [something]
Common mistake:
Learners often confuse "complement" with "compliment". "Complement" (with an "e") is about completing or going well with something: "The sauce is a perfect complement to the meat." "Compliment" (with an "i") means praise: "He gave her a compliment on her cooking." Another mistake is using the wrong preposition; for this sense it is usually "a complement to" something, not "a complement of".
Synonyms
counterpart (Often stresses a matching part or equivalent in another place or system, not always about improving or completing.)
|
match (More general and informal; can mean simply that two things go well together, without the idea of completion.)
|
supplement (Focuses on adding something extra that is missing; less about natural harmony and more about filling a gap.)
Antonyms
clash (Used especially about colors, styles, or ideas that do not go well together.)
|
mismatch (Emphasizes that two things do not fit or work well together.)
Collocations
perfect complement
|natural complement
|ideal complement
|complement to
|serve as a complement
|provide a complement
Themes
relationships
|description
|daily life
|daily_life
|core_vocabulary
Examples
- This crisp white wine is the perfect complement to spicy seafood dishes.
- Her calm, methodical style is a great complement to his energetic approach.
- The new app is designed as a complement to the existing desktop software.
- A side salad makes a light complement to the rich main course.
- The scarf is a colorful complement to her otherwise plain outfit.
Learner examples
- Rice is a good complement to many meat dishes.
- His skills are a strong complement to the team.
- The sauce is a nice complement to the fish.
- This book is a useful complement to the main textbook.
- The red shoes are a fun complement to her black dress.
Verb
B2
action
2
to complete or go well with
To go well with something and make it better or more complete.
Usage pattern:
[something] complements [something]
Common mistake:
Learners often write *"compliment"* instead of "complement" for this meaning, especially after hearing it. Remember: "complement" is used when two things go well together ("The shoes complement the dress"), while "compliment" is used when you say something nice to someone ("He complimented her dress"). Another mistake is adding "with": in most cases we say "X complements Y", not *"complements with Y"*.
Synonyms
enhance (Focuses more on improving quality, not always on completing or balancing another thing.)
|
balance (Stresses creating harmony or evenness; may not always imply completion.)
|
go with (More informal; often used about clothes, colors, or food that look or taste good together.)
Antonyms
clash (Used especially for colors, designs, or styles that look bad together.)
|
conflict (Emphasizes that two things do not work or fit well together.)
Collocations
complement each other
|complement [something] perfectly
|colors that complement
|flavors that complement
|skills that complement
|designed to complement
Themes
relationships
|description
|arts
|daily_life
|core_vocabulary
Examples
- The light curtains complement the dark wooden floor beautifully.
- Their skills complement each other, so they make a strong team.
- A squeeze of lemon really complements the flavor of the fish.
- This software is meant to complement, not replace, traditional teaching.
- The new regulations are designed to complement existing safety laws.
Learner examples
- The blue shirt complements his eyes.
- These two colors complement each other well.
- Her soft voice complements the quiet music.
- This small course will complement your main studies.
- The new app complements the website.
Noun
C1
quantity
3
full number or amount needed
The full group or amount that is needed or usual in a situation.
Usage pattern:
a full complement of [people/things]
Common mistake:
Learners sometimes think this sense means "extra" people or things, but it actually means the full, correct number. Another error is using it without an article; in most cases you say "a full complement of" rather than just *"full complement of"* in standard written English.
Synonyms
full staff (Informal and specific to employees; does not work well with non-human things.)
|
full quota (Often used when a fixed, allowed number is involved; slightly more technical.)
|
entire roster (Used more about lists of people such as teams; less general than "complement".)
Antonyms
shortage (Highlights having too few people or things compared with what is needed.)
|
understaffing (Specific to not having enough staff or workers.)
Collocations
a full complement of staff
|a full complement of crew
|entire complement
|carry a complement of
|complement of officers
Themes
work
|organization
|transport
|core_vocabulary
Examples
- The hospital finally has a full complement of doctors on the night shift.
- The ship sailed with a complement of 200 passengers and 50 crew.
- We will open the new branch as soon as we reach a full complement of staff.
- The board now has its full complement of ten members.
- The aircraft took off with a full complement of fuel and supplies.
Learner examples
- The hotel does not have a full complement of workers yet.
- The bus left with a full complement of passengers.
- Our team now has a full complement of players.
- The office will run better with a full complement of staff.
- The ship carried a complement of 30 sailors.
Noun
technical
C1
entity
4
set of all elements not in a set
In mathematics, all the items in the whole group that are not in a smaller group you are talking about.
Usage pattern:
the complement of [set A] (in [set B])
Common mistake:
Students sometimes confuse the complement of a set with its subset. A complement contains all elements not in the set (relative to some universal set), while a subset contains elements that are inside the set.
Synonyms
set-theoretic complement (More explicit and technical term used in mathematics texts.)
Antonyms
subset (Not a strict logical opposite, but contrasts with focusing on elements inside the set instead of outside it.)
Collocations
the complement of A
|set complement
|relative complement
|complement in the universal set
|complement of a subset
Themes
mathematics
|education
|science
Examples
- If U is the universal set and A is a subset of U, then the complement of A is written as A′ or Ac.
- In this exercise you must find the complement of the shaded region in the Venn diagram.
- The complement of the set of even numbers, within the integers, is the set of odd numbers.
Learner examples
- In the picture, the white area is the complement of set A.
- The teacher asked us to find the complement of B in the universal set U.
- In a Venn diagram, the complement is everything outside the circle for that set.
Noun
technical
C1
entity
5
grammatical element completing meaning
In grammar, a word or group of words that you must add to a verb, noun, or adjective so that the sentence has a complete meaning.
Usage pattern:
a [subject/object] complement
Common mistake:
Learners often confuse complements with adjuncts. A complement is required to complete the meaning of the verb ("She put the book on the table" — "on the table" is a complement), but an adjunct is extra information that can be removed ("She read the book yesterday" — "yesterday" is an adjunct).
Synonyms
predicative (Technical term often used for complements linked to the subject via a linking verb; more specific than "complement".)
Antonyms
adjunct (In grammar, an optional part of the sentence that is not required to complete the meaning of the verb.)
Collocations
subject complement
|object complement
|verb complement
|clausal complement
|complement of the verb
Themes
linguistics
|education
|language
|communication
Examples
- In the sentence "She is a doctor", the noun phrase "a doctor" functions as a subject complement.
- Some verbs, like "consider", can take an object complement, as in "They considered him a friend."
- The clause "that she was late" is a clausal complement of the verb "explained" in this sentence.
Learner examples
- In "He became tired", the word "tired" is a subject complement.
- In "We named the dog Max", the word "Max" is an object complement.
- Your teacher may ask you to underline the complement in the sentence.
Grammar
Dictionary form
complement
IPA
GB/kˈɑmpləmənt/
US/kˈɑmpləmənt/
Syllables & stress
com - ple - ment (3 syllables)
Stress on 1st syllable (com)
Word forms
Noun
- Base: complement
- Plural: complement, complements
Verb
- Base: complement
- 3rd Person Singular: complements
- Present Participle: complementing
- Past: complemented
Word family
Forms
complements
noun
complementing
verb
complemented
verb
Core family
complementary
adjective B2
Related words
Negative and opposite forms
incomplete
adjective B1
Advanced or less common
complementarity
noun
Expressions
a full complement of [something]
1/ə fˈʊl kˈɑmpləmənt əv sˈʌmθɪŋ/
fixed phrase
the complete number needed
Used to say that you have the full number of people or things that you need or expect.
Examples
- We finally have a full complement of staff for the summer season.
- The plane took off with a full complement of passengers and crew.
a perfect complement to [something]
1/ə pˈɚfɛkt kˈɑmpləmənt tə sˈʌmθɪŋ/
fixed phrase
ideal thing that completes something
Used to say that one thing goes extremely well with another thing and makes it better or complete.
Examples
- This sharp cheddar is a perfect complement to the sweet apple slices.
- Her technical knowledge is a perfect complement to his sales experience.
complement each other
1/kˈɑmpləmənt ˈit͡ʃ ˈʌðɚ/
fixed phrase
mutually complete or enhance each other
Used when two or more people or things go very well together and make each other better or more complete.
Examples
- Their personalities complement each other; she is patient and he is decisive.
- The sweet sauce and the salty meat really complement each other.
serve as a complement to [something]
1/sˈɚv ˈæz ə kˈɑmpləmənt tə sˈʌmθɪŋ/
fixed phrase
formal
function to complete or support
Used in more formal English to say that something has the job of completing or supporting something else.
Examples
- The online course is designed to serve as a complement to classroom teaching.
- Local buses serve as a complement to the city’s train network.