المعنى الاصطلاحي :

The divergence between nouns and names.

الشرح المختصر :

“Takhāluf” (antonymy) occurs between two names or nouns when each of them has a meaning that is different from the one applying to the other, like a man and a stone, neither of them can be applied to one another. If one of the two different entities is existent while the other is non-existent, then they are "naqeedān" (two contradictories) that can neither be present together nor absent together at the same case, such as day and night. If both of them are existent, but cannot be present together, yet they can be absent together like man and stone, which are "diddān" (two opposites). In fact, man and stone are opposites, so they cannot be present in the same entity. If realizing one of the meanings is contingent upon realizing the other, then they are "mutadāyifān" (mutually attached), like a father and a son. For instance, Zayd cannot be a father and son at the same time, yet he can be a father to another person. A father can not be imagined without a son, neither can a son be imagined without a father. If one of them is existent and the other is non-existent, but it is possible for the non-existent to be existent, then it is a case of loss and possession, like blindness and sight. That is, blindness is the loss of sight by someone who could have eyesight.

التعريف اللغوي المختصر :

“Takhāluf”: opposition, divergence, inconsistency.