exigency (n.)

1580s, "that which is needed," from Middle French exigence, from Latin exigentia "urgency," from exigentem (nominative exigens), present participle of exigere "demand, require, enforce," literally "to drive or force out," also "to finish, measure," from ex "out" (see ex-) + agere "to set in motion, drive, drive forward; to do, perform" (from PIE root *ag- "to drive, draw out or forth, move"). Meaning "state of being urgent" is from 1769. Related: Exigencies (1650s).