Nerve  —n. 1 a fibre or bundle of fibres that transmits impulses of sensation or motion between the brain or spinal cord and other parts of the body. B material constituting these. 2 a coolness in danger; bravery. B colloq. Impudence. 3 (in pl.) Nervousness; mental or physical stress. —v. (-ving) 1 (usu. Refl.) Brace (oneself) to face danger etc. 2 give strength, vigour, or courage to.  get on a person's nerves irritate a person. [latin nervus sinew, bowstring]