antisymmetric

adjective Mathematics.

1. noting a relation in which one element’s dependence on a second implies that the second element is not dependent on the first, as the relation “greater than.”

adjective

1. logic (of a relation) never holding between a pair of arguments x and y when it holds between y and x except when x = y, as “…is no younger than…”See nonsymmetric
2. maths symmetric except for a change of signCompare asymmetric, symmetric (def. 1)