complementary

complementary — adjective

1. describes two things or people that combine well because each supplies qualities

1.adjectiveB2
Definition

describes two things or people that combine well because each supplies qualities or features that the other lacks, creating a more complete or effective whole.

Example

Leila's calm approach and Ravi's energetic style are complementary — they balance each other at work.

be complementary — describing people's contrasting qualities

The two departments provide complementary services — one handles design while the other manages production.

complementary services — business context

Common collocations
  • complementary skills
  • complementary roles
  • complementary services
  • complementary strengths
  • complementary partnership
  • complementary relationship
Synonyms
  • matching

    suggests similarity or likeness; complementary things are typically different, not alike

  • compatible

    focuses on coexistence without conflict, not on mutual completion

  • corresponding

    emphasises a systematic one-to-one alignment rather than filling gaps

  • supplementary

    means added extra; complementary implies mutual completion, not simple addition

Antonyms

Grammar Patterns

be complementary to [noun/noun phrase]

Usage Note

Often used with 'to' (a skill complementary to another). Also common in business and team contexts to describe departments, roles, or people that together cover a full range of needs without unnecessary overlap.

Common Mistakes

The hotel offers a complementary breakfast.
The hotel offers a complimentary breakfast.
'Complementary' means combining well; 'complimentary' means given free of charge.

2. describes a pair of colours that produce black, white, or grey when combined in

2.adjectiveB2
Definition

describes a pair of colours that produce black, white, or grey when combined in the right amounts, and create a vivid contrast whenever they appear alongside each other — for example, red and green, blue and orange, or yellow and purple.

Example

Green and red are complementary colours that create strong contrast when used together in design.

complementary colours + visual contrast — colour theory

The designer chose complementary shades of blue and orange for the hotel lobby.

complementary shades — artistic choice

Common collocations
  • complementary colour
  • complementary shade
  • complementary scheme
  • complementary pair
  • complementary hue

Grammar Patterns

complementary colour

complementary shade

complementary to [colour name]

Usage Note

In colour theory every colour has exactly one complementary colour — the colour opposite it on the colour wheel. Artists and designers rely on complementary pairs to create visual energy and balance. This sense is almost always used attributively (before a noun).

Word family

Synonym discussion

Sense: adjective/1

While matching, compatible, corresponding, and supplementary all relate to things that go together, complementary has a distinct core: the items are deliberately different, and each supplies what the other lacks. Matching items are similar or even identical (matching chairs around a table), not different. Compatible things can coexist without conflict, but that is about tolerance rather than mutual completion — two colleagues with the same approach may be compatible but not complementary. Corresponding items occupy parallel positions in a system (corresponding chapters in two books) without necessarily completing each other. Supplementary items add extra content (a supplementary reading list) but do not fill a structural gap. Use complementary when two distinct elements — skills, personalities, flavours — combine to form a more complete whole: 'The teacher's structured lessons and the assistant's playful activities were complementary, not competitive.'

matching ↗compatible ↗corresponding ↗supplementary ↗

Common collocations

Adverbs

  • perfectly complementary
  • mutually complementary

Prepositions

  • complementary to

Etymology

LatinFrenchEnglish

Complementary comes from late Latin complementum, meaning 'that which fills up or completes', from the verb complere (com- 'together' + plere 'to fill'). It entered English through French in the 1600s, first as complement (a noun for what completes something), which later gave rise to the adjective complementary. The colour-theory sense developed in the 1800s alongside scientific colour wheels. Do not confuse with complimentary (meaning free or praising), which comes from a different Italian-influenced branch of the same Latin root.