khaki

Khaki comes from Hindustani خاکی / ख़ाकी (xākī), itself from Classical Persian خَاکِی (xākī), meaning "dusty, earthy, earth-colored."

The word originally just described the color of dust or earth, but it took on a specific new meaning as a noun for the drab, earth-toned uniform worn by British troops in the Second Boer War.

The facts note that khaki in this military sense can be compared with "rooinek," another term tied to the same conflict, though no direct etymological kinship between the two is given.