Meaning

noun any bundle of nerve fibers running to various organs and tissues of the body

noun the courage to carry on

noun impudent aggressiveness

originRecorded since circa 1374 as Middle English nerve, from Medieval Latin nervus (“nerve”), from Latin nervus (“sinew”). Doublet of neuron and sinew. Verb sense 4 (“to get on (someone’s) nerves”) is chiefly a semantic loan from German nerven.

Etymology from Wiktionary, CC BY-SA 3.0