1911 Encyclopædia Britannica/Motley

MOTLEY, i.e. of many colours, a term particularly used of the parti-coloured dress of the professional “fool” (q.v.) of the middle and later ages. The origin of the word is probably to be found in “mote” (O. Eng. mot), a particle of dust, &c., hence a spot or patch. “Mottle,” a blotch or spot, is probably a back formation of motley.