to act against or provide resistance to; combat.

to stand in the way of; hinder; obstruct.

to set as an opponent or adversary.

to be hostile or adverse to, as in opinion

to oppose a resolution in a debate.

to set as an obstacle or hindrance.

to set against in some relation, esp. as to demonstrate a comparison or contrast

to oppose advantages to disadvantages.

to use or take as being opposite or contrary.

to set (something) over against something else in place, or to set (two things) so as to face or be opposite to one another.

to be or act in opposition.

adjective

adversarial , adverse , antagonistic , antipathetic , opposed , oppositional , antipodal , antipodean , antithetical , antonymic , antonymous , contradictory , contrary , converse , counter , diametric , diametrical , polar , reverse , anti , at variance , conflicting , contending , opposite , rival