in physical sense: P. νεῦρον, τό (late).
courage: P. and V. θάρσος, τό, θράσος, τό, φρόνημα, τό, θυμός, ὁ, Ar. and V. λῆμα, τό.
nerves (feelings generally): use P. and V. ψυχή, ἡ.
encourage: P. and V. θαρσύνειν, θρασύνειν, P. ἐπιρρωνύναι.