complement or supplement? Both these words convey the idea of adding something. If one thing complements another, however, it goes well with it and enhances it when they are put together: A hat should complement the rest of one's outfit, not draw attention to itself. If one thing supplements another, it adds to it and reinforces it: She supplements her income by giving private music lessons. A good wine may be a complement to a meal, but a person might need a dietary supplement if some essential element is lacking from the food they normally eat. Note that neither of these words is spelt with an i. See also note at compliment¹