Two words - life and death, yes and no, black and white - precisely or approximately opposite each other in meaning are called antonyms. By and large, antonyms have received little attention in the logological realm. Exceptions have been two opposite concepts expressed by the same word (TEMPER means both "to harden" and "to soften") and two words anatomic in their most obvious senses which are synonyms in some other sense (to "best" and to "worst" both mean "to get the better of"). Some words have numerous antonyms, phenomenon one of synonym rather than of antonymy.
Borgmann, Dmitri A.
"Sets of Mutually Antonymic Words,"
Word Ways: Vol. 21
, Article 6.
Available at: http://digitalcommons.butler.edu/wordways/vol21/iss1/6