Complementary vs. Complimentary: How to Choose the Right Word

Like the nouns and verbs they come from, "complement" and "compliment," the derived adjectives "complementary" and "complimentary" can be confusing. These word pairs are homophones; in other words, they sound alike but have different meanings. One describes a perfect partnership and the other expresses appreciation or praise.

Learn how to use each of these words in a sentence.

How to Use Complementary

The adjective "complementary" (with an "e" in the second syllable) means serving to complete or supply mutual needs. Two or more parts that come together to make a better whole are called complementary.

Complementary acute angles, when added together, make a right or 90-degree angle. Complementary colors of light, when combined, produce colorless white light. Complementary objects go together: pen and paper, needle and thread, horse and carriage, bow and arrow.

How to Use Complimentary

The adjective "complimentary" (with an "i" in the second syllable) means flattering and favorable or given free as a courtesy. Derived from the noun "compliment," "complimentary" can be used to describe a person or person's action (a complimentary performance review means a positive performance review) or an item or service that's provided for no cost (i.e., complimentary tickets, often abbreviated "comp tickets", are free of charge).

Examples

"Complementary" is used to describe separate elements that together equal perfection, make a whole, or are supplementary or reciprocal. This adjective can be used to refer to people, animals, objects, or concepts:

• Complementary relationships between two or more things or people are highly functional: I've never seen a better complementary working partnership than that of Jess and Laura; they are a true yin and yang in our workplace. Jess and Laura work favorably together.
• Complementary objects pair well together and are pleasing when combined: This wine and cheese are perfectly complementary. The wine and cheese are better together than they are separate.

"Complimentary" is used in reference to flattering or praising someone or giving something away for free:

• When someone is being complimentary, they are praising and flattering someone or something else: Sonia was quite complimentary about your friendliness and warmth to her when her spouse was ill.
• The casino offers a complimentary buffet to gamblers. The buffet is free to gamblers.
• Most sports organizations provide at least two complimentary tickets per game to players, coaches, administrators, and full-time staff members. The game tickets are free to players, coaches, etc.

How to Remember the Difference

When you want to describe something that's "complementary," two or more parts that work together well, think of the word "complete": "Complementary" things complete one another, and both have an "e" in their second syllable. "Complimentary," with an "i," means containing a "compliment," which is "an expression of esteem, respect, affection, or admiration," ("compliment").

Sources

• “Complementary.” Merriam-Webster.
• "Compliment." Merriam-Webster.
• "Complimentary." Merriam-Webster.
• “Compliment, Complement.” The Chicago Manual of Style. 15th ed., The University of Chicago Press, 2003.
• Fogarty, Mignon. “Complement versus Compliment.” Grammar Girl's 101 Misused Words You'll Never Confuse Again. St. Martin's Publishing Group, 2011.