Meaning

noun a sturdy twilled cloth of a yellowish brown color used especially for military uniforms

adjective of a yellowish brown color

originBorrowed from Hindustani خاکی (xākī) / ख़ाकी (xākī), from Classical Persian خَاکِی (xākī, “dusty, earthy, earth-colored”). Noun sense 5 was coined in reference to the colour of the uniform of British troops during the Second Boer War; compare rooinek.

Etymology from Wiktionary, CC BY-SA 3.0