exigency

The demands or requirements of a situation.

My business is with you, and you only. You should not have undertaken your office, unless prepared for its various exigencies.

No ordinary man could have escaped those frightful claws when Numa sprang from so short a distance, but Tarzan was no ordinary man. From earliest childhood his muscles had been trained by the fierce exigencies of his existence to act with the rapidity of thought.

An urgent situation, one requiring extreme effort or attention.