perverse
Pronunciation: /pəˈvəːs/
adjective
- 1showing a deliberate and obstinate desire to behave in a way that is unreasonable or unacceptable: Kate’s perverse decision not to cooperate held good


Origin:
late Middle English (in the sense 'turned away from what is right or good'): from Old French pervers(e), from Latin perversus 'turned about', from the verb pervertere (see pervert)