Definition of "downfall"

The Black Cats contributed to their own downfall for the only goal when Titus Bramble, making his first appearance since Boxing Day, and Michael Turner, let Phil Jones' cross bounce across the six-yard box as [Wayne] Rooney tucked in at the back post.

2012 May 13, Alistair Magowan, “Sunderland 0 – 1 Man Utd”, in BBC Sport‎, archived from the original on 9 May 2019

It is the downfall of evil, that it never sees far enough ahead.

Orson Scott Card

[T]he prominent character of leading young lady or heroine, which Paula was to personate, was really the most satisfactory in the whole list for her. For although she was to be wooed hard, there was just as much love-making among the remaining personages; while, as Somerset had understood the play, there could occur no flingings of her person upon her lover's neck, or agonized downfalls upon the stage, in her whole performance, [...]

1880–1881, Thomas Hardy, chapter VII, in A Laodicean; or, The Castle of the De Stancys. A Story of To-day. […], volume II, London: Sampson Low, Marston, Searle & Rivington, […], published 1881, book the third (De Stancy), page 147

[...] wants to make civilization his subject, he will have a hard time proceeding with the sentence unless collapse is in his active vocabulary, for he cannot say "our civilization will downfall" or "fall down."

1977, Mina P. Shaughnessy, Errors and expectations: a guide for the teacher of basic writing

Common belief has been that in the future the number of middle managers will downfall due to empowerment and team-building.

1998, Peter Vink, Ernst A. P. Koningsveld, Steven Dhondt, Human factors in organizational design and management-VI

It should be noted that the magnitude of satellites decreases when tuning out of degeneracy, and in the wavelength range of 1.2-1.3 pm it downfalls to the value of 10-15% of the main spike magnitude.

1998, Lithuanian physics journal

[...] As goodly air as ever From lunar orb downfell— Be it by hazard, Or supervened it by arrogancy?

2008, Friedrich Wilhelm Nietzsche, Thus Spake Zarathustra