Either of a pair of propositions, that cannot both be true or both be false.
That contradicts something, such as an argument.
That is diametrically opposed to something.
That is itself a contradiction.
Mutually exclusive.
Tending to contradict or oppose, contrarious.
Of a proposition or theorem of the form: given that "If A is true, then B is true", then "If B is true, then A is true.".
Free verbal interchange of thoughts or views; conversation; chat.
The opposite or reverse.
One of a pair of terms that name or describe a relationship from opposite perspectives; converse antonym; relational antonym.
To keep company; to hold intimate intercourse; to commune.
To talk; to engage in conversation.
opposite; reversed in order or relation; reciprocal