One of a pair of propositions that cannot both be simultaneously true, though they may both be false.
The opposite.
Contrarily
Opposite; in an opposite direction; in opposition; adverse.
Opposed; contradictory; inconsistent.
Given to opposition; perverse; wayward.
An incommensurable value or quantity; an irrational number.
Not able to be measured by the same standards as another term in the context.
having a ratio that is not expressible as a fraction of two integers.
having no common integer divisor except 1.