ANTHORISMUS, in Rhetoric, denotes a contrary description or definition of a thing from that given by the adverse party. Thus, if the plaintiff urge, that to take any thing away from another without his knowledge or consent, is a theft; this is called opos, or definition. If the defendant reply, that to take a thing away from another without his knowledge or consent, provided it be done with design to return it to him again, is not theft; this is an antithesis.