deprave

Concise Oxford English Dictionary © 2008 Oxford University Press:
deprave /dɪˈpreɪv/

▶verb make (someone) immoral or wicked; corrupt.

– derivatives
depravation noun,
depravity /dɪˈpravɪti/ noun (pl. depravities).

– origin ME (in the sense ‘pervert in meaning or intention’): from OFr. depraver or L. depravare, from de- ‘down, thoroughly’ + pravus ‘crooked, perverse’.