exigency

exigency \EK-suh-jun-see; ig-ZIJ-un-see\, noun:

1. The quality or state of requiring immediate aid or action; urgency.
2. A case demanding immediate action or remedy; a pressing or urgent situation.
3. That which is demanded or required in a particular situation -- usually used in the plural.

Finally, in late 1961 and early 1962, naked exigency forced the Chinese Communist Party to recognize the extent of the crisis it had created. The most deadly innovations from the Great Leap Forward were quietly abandoned or reversed; almost immediately, this artificially manufactured famine came to an end.
-- Nicholas Eberstadt, "The Great Leap Backward", review of Hungry Ghosts: Mao's Secret Famine, by Jasper Becker, New York Times, February 16, 1997

But rearing and educating babies required women to prepare for exigencies that could occur decades down the road.
-- Helen Fisher, The First Sex

Better than any other species, they had adapted to the exigencies of the Ice Ages.
-- David Fromkin, The Way of the World: From the Dawn of Civilizations to the Eve of the Twenty-first Century

Exigency comes from Medieval Latin exigentia, from the present participle of Latin exigere, to drive out, to force out, to exact, to demand, from ex-, out of + agere, to drive. The adjective form is exigent.