This question reveals the history of the peppermint sweet's name, but does not elabourate on how the word was first formed.
At first glance, it would seem to be a portmanteau or the like just from the word "bug"; is this at all pertinent?
Etymonline is left clueless, quoting the OED who appear that have also given up:
1751, student slang, "trick, jest, hoax, imposition, deception," of unknown origin. Also appearing as a verb at the same time, "deceive by false pretext" (trans.). A vogue word of the early 1750s; its origin was a subject of much whimsical speculation even then. "[A]s with other and more recent words of similar introduction, the facts as to its origin appear to have been lost, even before the word became common enough to excite attention" [OED].
I'm sure the users of EL&U can dig deeper and find out where exactly the word humbug comes from.
Can you build on "unknown origin"?
Best Answer
One thing you can do with terms with unknown origin is to consider all possible sources. Here is a list of the more common theories about humbug etymology;
Humbug, from (maps.thefullwiki.org):
References: (www.americanheritage.com) www.etymologie.info Svenska Akademiens ordbok s.v. Humbug Dictionnaire de la Langue Francais, Littré 1872-1877 Wiktionary V.K. Müller, Russian-English Dictionary 1911encyclopedia.org Charles Godfrey Leland, Gypsy Sorcery and Fortune Telling [1891], Chapter X of The Haunts, Homes, and Habits of Witches in The South Slavic Lands--Bogeys and Humbugs Svenska Akademiens ordbok s.v. Hum Svenska Akademiens ordbok s.v. Hymla Dictionary of the Vulgar Tongue dictionary.com 1911 Encyclopedia s.v. Humbug Factmonster 1911 Encyclopedia 1911 Encyclopedia word-detective