vitiate

(verb) corrupt morally or by intemperance or sensuality. Synonyms: corrupt, pervert, subvert, demoralize, demoralise, debauch, debase, profane, deprave, misdirect. Examples: "Debauch the young people with wine and women." "Socrates was accused of corrupting young men." "Do school counselors subvert young children?." "Corrupt the morals."

(verb) make imperfect. Synonyms: mar, impair, spoil, deflower. Example: "Nothing marred her beauty."

(verb) take away the legal force of or render ineffective. Synonyms: invalidate, void. Example: "Invalidate a contract."