(2) Complementary Antonyms
"Complementary antonyms are another subtype of antonymy: if you are one, you cannot be the other; these are 'absolute' opposites. That is, if you are dead, you cannot also be alive; if you are asleep, you are not awake, and so on. Similar pairs of this sort include legal/illegal and beginning/end."
(Kristin Denham and Anne Lobeck, Linguistics for Everyone: An Introduction, 2nd ed. Wadsworth, 2013)