- (semantics) A term whose meaning is the complement of another term, in an either-or fashion, such as mortal in relation to immortal.
- (linguistics, philosophy, semantics) One of a pair of words wherein affirmative use of one entails the negative of the other with no gradability.
- 2010, M. Lynne Murphy, Lexical Meaning, page 120:
- Complementary (also called contradictory) antonyms are those for which the assertion of one entails the negation of the other and vice versa, as in (17).
a. That integer is even. → That integer is not odd.
b. That integer is not odd. → That integer is even.