Adversative

a.	1.	Expressing contrariety, opposition, or antithesis; as, an adversative conjunction (but, however, yet, etc. ); an adversative force.
n.	1.	An adversative word.

Adj.

1.

adversative - expressing antithesis or opposition; "the adversative conjunction `but' in `poor but happy'" Synonyms: oppositive

disjunctive, oppositive