opposite in nature or character; diametrically or mutually opposed

contrary to fact; contrary propositions.

opposite in direction or position

departures in contrary directions.

being the opposite one of two

I will make the contrary choice.

unfavorable or adverse.

perverse; stubbornly opposed or willful.

something that is contrary or opposite

to prove the contrary of a statement.

either of two contrary things.

Logic . a proposition so related to another proposition that both may not be true though both may be false, as with the propositions All judges are male and No judges are male.

in opposition; oppositely; counter

to act contrary to one's own principles.

by contraries

contrary to expectation.

on the contrary

in opposition to what has been stated.

from another point of view

On the contrary, there may be some who would agree with you.

to the contrary

to the opposite effect

I believe he is innocent, whatever they may say to the contrary.

to a different effect.

noun

antagonism , antithesis , contradiction , contradistinction , contraposition , contrariety , polarity