Exigent

Part of speech: noun (n.)

1. Exigency; pressing necessity; decisive moment. [Obs.] Why do you cross me in this exigent Shak.

2. The name of a writ in proceedings before outlawry. Abbott.

Part of speech: adjective (a.)

Exacting or requiring immediate aid or action; pressing; critical. "At this exigent moment." Burke.