Complementary vs. Complimentary: How to Choose the Right Word

What fits together and what's free for the asking?

The hugs being offered by these women are complimentary (free of charge)

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

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.

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

"Complementary" is derived from the noun "complement," which means that which "fills up, completes, or makes better or perfect."

How to Use "Complimentary"

The adjective "complimentary" (with an "i" in the second syllable) means flattering or favorable or given free as a courtesy. Derived from the noun "compliment," "complimentary" can be used to describe a person or an action by that person (a complimentary performance review means a positive performance review) or an item or service that is provided without cost (complimentary tickets means free tickets, often abbreviated as comp tickets).

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, other animals, objects, or concepts:

  • 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.
  • This wine and cheese are perfectly complementary.

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

  • Sonia was quite complimentary about your friendliness and warmth to her when her spouse was ill.
  • The casino offers a complimentary buffet to gamblers.
  • Most sports organizations provide at least two complimentary tickets per game to players, coaches, administrators, and full-time staff members.

How to Remember the Difference

When you want to describe something that is "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."

Sources

  • Complementary.” Merriam-Webster, Merriam-Webster.
  • "Compliment." Merriam-Webster, Merriam-Webster.
  • “Compliment, Complement.” The Chicago Manual of Style, 15th ed., The University of Chicago Press, 2003, p. 207.
  • "Complimentary." Merriam-Webster, Merriam-Webster.
  • Fogarty, Mignon. “Complement versus Compliment.” Grammar Girl's 101 Misused Words You'll Never Confuse Again, St. Martin's Griffin, 2011, p. 35.