perverse

Concise Oxford English Dictionary © 2008 Oxford University Press:
perverse/pəˈvɜːs/

▶adjective

• 1 showing a deliberate and obstinate desire to behave unacceptably.

  ■ sexually perverted.

• 2 contrary to that which is accepted or expected.

  ■ Law (of a verdict) against the weight of evidence or the direction of the judge.

– derivatives
perversely adverb,
perverseness noun,
perversity noun (pl. perversities).

– origin ME: from OFr. pervers(e), from L. perversus, pervertere (see pervert).