Complementary describes things that complete, balance, or enhance each other. The idea is a useful combination: each part contributes something the other lacks. For example, “Maya’s design skills are complementary to Leo’s technical expertise.” The skills differ, but together they form a stronger team.
You can also use complementary for flavors, colors, services, therapies, or viewpoints that work well together. “The citrus and herbs have complementary flavors” means the flavors support each other, not that they are praising each other.
Complimentary has two common meanings. First, it can describe praise or approval. “The editor was complimentary about the revised article” means the editor spoke favorably about it.
Second, complimentary can mean provided free of charge, often as a courtesy. “The hotel offers complimentary coffee in the lobby” means guests do not pay for the coffee. It does not mean the coffee completes something else.
Compare these uses:
- “Their complementary approaches solved the problem.” Their approaches worked well together.
- “Her comments were complimentary.” Her comments expressed praise.
- “Dessert was complimentary.” Dessert was free.
A practical spelling check is to connect complementary with complete. Both use an e after the l. If the meaning is praise or a free item, choose complimentary with an i.