Mottled means marked with patches of different shades. Mottled skin, a mottled leaf, mottled grey.
The patches are irregular and blended, which is what separates it from spotted or speckled. Mottled skin in a sick child is a warning sign worth acting on. In plants it can mean a virus. The word comes from motley, the many-coloured cloth.
1adjectivemottledMarked with patches of different shades.
“The old man's hands were mottled with brown spots.”
mottled is a quality of marking.
Probably a back-formation from motley, the parti-coloured cloth worn by a jester.
1670-80 mottle + ed.
Etymology from Wiktionary, CC BY-SA