antithetical

/ˌan-tə-ˈthe-ti-kəl/

adjective

  1. being in direct and unequivocal opposition : directly opposite or opposed

  2. constituting or marked by antithesis

… some see the idea of a museum for rock & roll as antithetical to the music's rebellious ethic …

opposite contradictory contrary antithetical mean being so far apart as to be or seem irreconcilable. opposite applies to things in sharp contrast or in conflict. contradictory applies to two things that completely negate each other so that if one is true or valid the other must be untrue or invalid.