(covers information from several alternate timelines)
A hobgoblin or simply goblin was a mythical creature originating from Earth folklore. They were often portrayed as friendly but mischievous little men found within Human dwellings.
In 2267, after the USS Enterprise computer suggested that an as-yet-unidentified non-corporeal entity could assume physical form, giving the mellitus of Alpha Majoris I as an example, Hengist rebuffed the idea, calling it "Fairy tales. Ghosts and goblins." James T. Kirk then assured him it was not a myth, as he himself had once seen the mellitus change form from a gas to a solid. (TOS: "Wolf in the Fold")
Doctor Leonard McCoy referred to Spock as a hobgoblin in 2268. He had attempted to show Spock gratitude for saving his life in the City Arena on 892-IV. Spock, however, was preoccupied with trying to find a means of escape from their imprisonment and asked the doctor to "be brief." Frustrated, McCoy replied, "I'm trying to thank you, you pointed-eared hobgoblin!" (TOS: "Bread and Circuses")
The Leonard McCoy of the alternate reality thought of his timeline's Spock as a hobgoblin, as well. In 2258 of that reality, McCoy voiced his extreme displeasure with that Spock's decision to maroon Jim Kirk on Delta Vega for mutiny. Spock showed no remorse for his actions and disagreed with McCoy's assertions, causing an infuriated McCoy to call Spock a "green-blooded hobgoblin." (Star Trek)
In 2376, upon learning of Seamus's suspicions that "Katie O'Clare" was one of the spirit folk, Michael Sullivan jokingly asked him if Katie was a goblin. (VOY: "Spirit Folk")
In a deleted scene from the Star Trek: The Next Generation seventh season episode "Sub Rosa", Ned Quint states that Beverly Crusher considered him to be “Just an old man with tales of ghosts and goblins.” [1]