קָדַר qâdar (H6937)

to be ashy, i.e. darkcolored; by implication, to mourn (in sackcloth or sordid garments)

1) to mourn, be dark 1a) (Qal) to be dark 1b) (Hiphil) 1b1) to darken 1b2) to cause to mourn 1c) (Hithpael) to grow dark

a primitive root;