Apparently passive participle of nachash (perhaps in the sense of ringing, i.e. Bell-metal; or from the red color of the throat of a serpent (nachash, as denominative) when hissing); coppery, i.e. (figuratively) hard -- of brass.
see HEBREW nachash
see HEBREW nachash
H5153. nachush
נָחוּשׁ adjective of bronze; — נ ׳אִםבְּֿשָׂרִי Job 6:12 or is my flesh of bronze ? figurative for strong, enduring ("" אֲבָנִים; compare 40:18 ).