Open English Wordnet
Nouns
(n)complementary color, complementaryeither one of two chromatic colors that when mixed together give white (in the case of lights) or grey (in the case of pigments)“yellow and blue are complementaries”
Adjectives
(s)complementaryof words or propositions so related that each is the negation of the other“`male' and `female' are complementary terms”
(s)complemental, complementary, completingacting as or providing a complement (something that completes the whole)