Are yams and sweet potatoes the same?
mid-14c., "demon," also in surnames (Isabella Ragamuffyn, 1344), from Middle English raggi "ragged" ("rag-y"?) + fanciful ending (or else second element is Middle Dutch muffe "mitten"). Or, as Johnson has it, "From rag and I know not what else." Ragged was used of the devil from c.1300 in reference to "shaggy" appearance. Raggeman was used by Langland as the name of a demon, and cf. Old French Ragamoffyn, name of a demon in a mystery play. Sense of "dirty, disreputable boy" is from 1580s. Cf. in the same sense ragabash (c.1600).