measles: [14] Measles means literally ‘spots, blemishes’. The word was originally borrowed from Middle Dutch māsel ‘blemish’, which went back to a prehistoric Germanic base *mas- ‘spot, blemish, excrescence’. The earliest English form of the word was thus maseles, and the change to measles (which began in the 14th century) may have been due to association with the now obsolete mesel ‘leper’, a descendant of Latin miser ‘wretched, unfortunate’ (source of English misery).
measles (n.)
infectious disease, early 14c., plural of Middle English masel, perhaps from Middle Dutch masel "blemish" (in plural "measles") or Middle Low German masele, from Proto-Germanic *mas- "spot, blemish" (cognates: Old High German masla "blood-blister," German Masern "measles").
There might have been an Old English cognate, but if so it has not been recorded. Form probably influenced by Middle English mesel "leprous" (late 13c.).