The Collaborative International Dictionary
Disennoble
Disennoble \Dis`en*no"ble\, v. t. To deprive of that which ennobles; to degrade.
An unworthy behavior degrades and disennobles a man.
--Guardian.
Wiktionary
disennoble
vb. (context transitive English) To deprive of what ennobles, to degrade.