Passive euthanasia means allowing a person to die by withholding an available treatment; allowing someone to die by either not doing that is withholding or omitting/withdrawing some action that is necessary to sustain life. It means withholding treatment or removing life-sustaining nourishment and breathing aids for the dying person, with the result that death occurs more quickly than if these procedures were continued.
Lexicon of Psychology - Terms, Treatments, Biographies,