Ob‐ver″sion (ŏb‐vẽr″shŭn), n. [L. obversio a turning towards.] 1. The act of turning toward or downward.
2. (Logic) The act of immediate inference, by which we deny the opposite of anything which has been affirmed; as, all men are mortal; then, by obversion, no men are immortal. This is also described as “immediate inference by privative conception.” Bain.