The weird usage seems to have developed in the same way as "a headquarters". Consider the following Ngram: The original phrase seems to have been "shambles" or "the shambles", almost always plural. It meant "a place for slaughtering animals", but later came to be also used for scenes of carnage, scenes of great disorder, and certain dangerous shoals at sea. Etymonline says that "shambles ...
nouns - Origin and usage of "a shambles" - English Language & Usage ...
I'm looking for an idiom that means 'a shambles' or 'a whole mess of various things', and any other reverse definitions of 'a whole mess of various things'. Perhaps "a mare's nest", which I've gat...
1 You could use " shambles ". (OLD) shambles noun /ˈʃæmblz/ [singular] (informal) a situation in which there is a great lack of order or understanding synonym mess The press conference was a complete shambles. What a shambles! He’s made an absolute shambles of his career. in a shambles: The government is in a shambles over Europe.
The word shambles, with or without the omni-, was once all about a literally bloody mess. The originals, still preserved in old British street names, were the stalls of medieval butchers whose wares of raw flesh and gore led to our modern use for something approaching carnage.
The full Oxford English Dictionary just says the -cock part of ballcock, shuttlecock,... comes from the male bird sense. Which is ALSO the origin for cock = penis (& derivatives like cock-up = shambles) AND cock = stand up straight (as a fishing float, or cocky = overconfident).