"side of fireplace," 1670s, alteration of hubbe (1510s), of unknown origin, perhaps somehow related to the first element in hobnail.
"clown, prankster," short for hobgoblin (q.v.). Hence, to play (the) hob "make mischief" (by 1834).
c. 1300, Hobbe, a variant of Rob, diminutive of Robert (compare Hick for Richard, Hodge for Rodger, etc.). Also a generic proper name for one of the common class.