(1):

(v. t.) To deprive of the qualities or properties necessary for any purpose; to render unfit; to incapacitate; - with for or from before the purpose, state, or act.

(2):

(v. t.) To deprive of some power, right, or privilege, by positive restriction; to disable; to debar legally; as, a conviction of perjury disqualifies a man to be a witness.