The
English use of the
adjective bloody as a vulgar, slang or swear word has caused a lot of consternation and bewilderment, amongst the English, for whom the origins of this use are lost in the mists of time, and amongst Americans, who consider it
quaint. In the latter half of the 20th Century, since sex has superseded war and religion as one of the major preoccupations of the English-speaking world (the other, of course, is
money), it has become popular to associate the word with menstrual discharge, but this is unlikely to have been in the minds of those who first made this usage popular, no matter whether they were warlike Saxons setting sail from mainland Europe cursing the 'bloedig' weather, or their descendants of any era taking
umbrage at something that displeased them.
In fact the origins of this use of the word are not difficult to reconstruct plausibly. The purpose of a swear word used in anger is typically to denigrate the object of one's ire, and so a hated thing will be considered 'tainted', either in a spiritual sense (unholy, cursed, damned), or a physical sense (dirty, bloody, shitty). Perhaps because of its vagueness and ambiguity, or its colourful implications, or simply because it sounds good, 'bloody' then quickly becomes not only an adjective conferring dishonour and loathing, but also a superlative, indicating an extra degree of abhorrence and anger about an already despised thing ('bloody fool', 'bloody idiot', and the phrase most commonly heard in England, 'bloody weather').