"gray in color," late 14c., griseld, a past-participle adjective formation from the noun grizzle "gray-haired old man" (early 14c. as a surname, Grissel); see grizzle (adj.). Or else from Old French grisel "gray," diminutive of gris "gray," from a Frankish or other Germanic source (such as Old High German gris "gray;" see gray (adj.). The -zz- spelling is early 15c. As a verb, grizzle "to grow gray; to make gray" is not attested before 18c.