From Middle High German unzuht (“immorality, vulgarity, rudeness”), from Old High German unzuht, analysable as un- + Zucht. Zucht originally means “discipline, education, manners”. Unzucht is derived thence, but was often restricted to the sexual sense already in early modern German. The simplex Zucht only later developed the additional sense “breeding”, with which Unzucht is now secondarily associated (“undue breeding”, as it were).
Unzucht f (genitive Unzucht, no plural)
- (also law, now chiefly religion) fornication; adultery; lewdness; promiscuity (any sexual behaviour considered immoral or forbidden)