Cōn’tra-ries, n. pl.

(kōn’tra-riz), n. pl. [See CONTRARY.] (Logic.) Propositions opposed in quality only, but of which the falsehood of one does not establish the truth of the other.

“If two universals differ in quality, they are contraries; as, every vine is a tree; no vine is a tree. These can never be both true together; but they may be both false.” Watts.