[in.verse] adj [L inversus, fr. pp. of invertere] (15c) 1: opposite in order, nature, or effect
2: being an inverse function "~ sine"
[2]inverse n (ca. 1681) 1: something of a contrary nature or quality: opposite, reverse
2: a proposition or theorem formed by contradicting both the subject and predicate or both the hypothesis and conclusion of a given proposition or theorem "the ~ of "if A then B" is "if not-A then not-B""--compare contrapositive 3 a: inverse function; also: an operation (as subtraction) that undoes the effect of another operation b: a set element that is related to another element in such a way that the result of applying a given binary operation to them is an identity element of the set