Where does “grauw” come from?

grauw (Dutch) comes from Middle Dutch grau, from Old Dutch grāo, from Proto-West Germanic *grāu, from Proto-Germanic grēwaz, from Proto-Indo-European ǵʰreh₁- — to become green, grow; to grow; to green, to grow.

grauw (Dutch): grey, not brightly colored, ashen, grubby, grimy;...