(Anglo-Celtic) Since, if you "speak of the Devil" he will appear, Puck's euphemistic "disguised" name is "Robin Goodfellow" or "Hobgoblin",in which "Hob" may substitute for "Rob" or may simply refer to the "goblin of the hearth" or hob. The name Robin is Middle English in origin, deriving from Old French Robin, the pet form for the name Robert (which had cognates in the Old English Hrodberht and Old German Rodbert or Hrodebert, all derived from the Proto-Germanic hrôdberxtas. See Robert). The earliest reference to "Robin Goodfellow" cited by the Oxford English Dictionary is from 1531. After Meyerbeer's successful opera Robert le Diable (1831), neo-medievalists and occultists began to apply the name Robin Goodfellow to the Devil, with appropriately extravagant imagery.
He is a mischievous imp who delights in pranks and hazings. Boastful and immature, at his best he resembles a kind of Tom Sawyer/Huck Finn figure, if you can imagine those two endowed with supernatural powers. His name is an Anglicized version of the Irish Puca, Cymric Pwcca, ancient Celtic hobgoblinish spirits having the same general attributes as the later figure.
Though often thought of today as the goat-footed faery king of the woodlands, Robin was probably once another name for the Horned God, and he is believed to be the source for the folk-tales about the forest-dwelling hero Robin Hood.