1598, from prp. stem of M.Fr. ternir
"dull the luster or brightness of, make dim" (15c.), probably from O.Fr. adj. terne
"dull, dark," from a Frank. source cognate with O.H.G. tarnjan
"to conceal, hide," O.E. dyrnan
"to hide, darken," from P.Gmc. *darnijaz,
related to dark
. Figurative sense is from 1697. The noun is recorded from 1713.