This article is from the Bulgaria FAQ, by Dragomir R. Radev firstname.lastname@example.org with numerous contributions by others.
(by Julian Dontchev), last updated: 26-Mar-1996
1. bugger - comes from the word Bulgarian, a name given to a sect
of heretics who came from Bulgaria in the 11th c., afterwards to
other `heretics' (to whom abominable practices were ascribed),
also to usurers.
2. bourge - OF. boulgre a `Bulgarian', a heretic: late L.
Bulgarus an inhabitant of Bulgaria.
10. sharka ! (used only for pox of plums)
There are other words of course that are not just Bulgarian, for
example moussaka, tsar, vampire... but the ones listed above are used
only in Bulgarian.
From: Oxford University Press, The Oxford English Dictionary
(Second Edition) On Compact Disc