c.1400, "affecting the sinews," from Latin nervosus "sinewy, vigorous," from nervus "sinew, nerve" (see nerve). Meaning "of or belonging to the nerves" in the modern sense is from 1660s. Meaning "suffering disorder of the nervous system" is from 1734; illogical sense "restless, agitated, lacking nerve" is 1740. Widespread popular use as a euphemism for mental forced the medical community to coin neurological to replace it in the older sense. Nervous wreck first attested 1862. Related: Nervously; nervousness.