inverse

If you notice that the more money you have, the less money your brother has, you’ve discovered an inverse relationship: when your bank account increases, his decreases.

The word inverse traces back to the Latin inversus, from the past participle of invertere, meaning “turn upside down" or "turn about.” It’s a good word to use when you need to describe one of those topsy-turvy relationships in which when one thing goes up, the other goes down. It can also be used in a broader sense to mean “opposite.” You’ve probably heard someone begin a sentence by saying, “And the inverse was true for so and so . . .” That just means the opposite was true.

Definitions of inverse
1

adj reversed (turned backward) in order or nature or effect

Synonyms:
reverse
backward
directed or facing toward the back or rear

adj opposite in nature or effect or relation to another quantity

“a term is in inverse proportion to another term if it increases (or decreases) as the other decreases (or increases)”
Synonyms:
reciprocal
of or relating to the multiplicative inverse of a quantity or function
Antonyms:
direct
similar in nature or effect or relation to another quantity

n something inverted in sequence or character or effect

“when the direct approach failed he tried the inverse
Synonyms:
opposite
Types:
additive inverse
(mathematics) one of a pair of numbers whose sum is zero; the additive inverse of -5 is +5
multiplicative inverse, reciprocal
(mathematics) one of a pair of numbers whose product is 1: the reciprocal of 2/3 is 3/2; the multiplicative inverse of 7 is 1/7
Type of:
oppositeness, opposition
the relation between opposed entities

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, Vocabulary.com can put you on the path to systematic vocabulary improvement.