exigency vs emergency

exigency and emergency both are nouns.

Word	Noun	Adjective	Verb	Adverb
exigency	Yes	No	No	No
emergency	Yes	No	No	No

As nouns, exigency and emergency are synonyms defined as:

exigency and emergency: a sudden unforeseen crisis (usually involving danger) that requires immediate action

Other synonyms of exigency include pinch.

exigency (noun)	emergency (noun)
a sudden unforeseen crisis (usually involving danger) that requires immediate action	a brake operated by hand; usually operates by mechanical linkage
a pressing or urgent situation	a sudden unforeseen crisis (usually involving danger) that requires immediate action
that which is required in a particular situation —usually used in plural.	a state in which martial law applies