"moral downfall" is correct and usable in written English.
It means the decline or decay of someone's moral standards or principles. For example, "The politician faced huge public criticism over his moral downfall."
The fortune he had amassed was sufficient to ensure the moral downfall of the next three generations".
So in a way, he engineered his own moral downfall – where he became hated among his own people.
A murderous blue-collar Boston mob boss turned FBI informant, his is the kind of inverted moral downfall that could be pulled from prime American crime cinema.
Civil war is the subject of "A Screaming Man," in which two forms of upheaval — physical violence and economic change — converge to bring about a decent man's moral downfall.
It might even have appeared that Prokofiev was self-indulgently taking Tolstoy's bait, since in the novel the scene of Natasha's moral downfall is set, in keeping with the author's harsh views, against the background of an opera performance compounded of recognizable bits of "Lucia di Lammermoor," "Il Trovatore" and other operas popular in Tolstoy's not Natasha's time.
Ms. Srbljanovic believes this fear "for our own naked existence," passed down like mother's milk from one generation to the next, must be supplanted with a "fear for our own moral downfall if we fail to speak" wherever repression, nationalism or immorality appear.
"Angel Face" is a story of the swift, inevitable moral decline and downfall resulting from one false move.
The sack of Rome was divine retribution for society's moral decline; Parmigianino's downfall was a result of his own artistic excess.
According to Muratov, the strategy paper also characterized Yanukovych as "a person without morals and willpower whose downfall must be expected at any moment".
The Deal Professor takes the opportunity to consider what Bear's downfall says about moral hazard, systemic risk and corporate governance.
This downfall represents a moral fault if the subject consents to it; if it is inflicted upon him, it spells frustration and oppression.
