1520s, from hob "elf," from Hobbe, a variant of Rob (see Hob), short for Robin Goodfellow, elf character in German folklore, + goblin. Mischievous sprite, hence "something that causes fear or disquiet" (1709).
Entries linking to hobgoblin
hob n.
"side of fireplace," 1670s, alteration of hubbe (1510s), of unknown origin, perhaps somehow related to the first element in hobnail.
goblin n.
early 14c., "a devil, incubus, mischievous and ugly fairy," from Norman French gobelin (12c., as Medieval Latin Gobelinus, the name of a spirit haunting the region of Evreux, in chronicle of Ordericus Vitalis), of uncertain origin; said to be unrelated to German kobold (see cobalt), or from Medieval Latin cabalus, from Greek kobalos "impudent rogue, knave," kobaloi "wicked spirits invoked by rogues," of unknown origin. Another suggestion is that it is a diminutive of the proper name Gobel.
Though French gobelin was not recorded until almost 250 years after appearance of the English term, it is mentioned in the Medieval Latin text of the 1100's, and few people who believed in folk magic used Medieval Latin. [Barnhart]
Thou schalt not drede of an arowe fliynge in the dai, of a gobelyn goynge in derknessis [Psalms xci.5 in the later Wycliffe Bible, late 14c.]