Folk etymology

Folk etymology, or popular etymology, refers to the supposed origin of words and expressions. Often on a par with urban myths, folk etymologies are widespread and oft-repeated by journalists, language pundits, and even English teachers have been known to put their foot in it when they haven't done their homework properly and merely repeat what they've heard or read somewhere...

Etymology itself being a pretty risky business, it leaves plenty of scope for folk to come up with their own hare-brained ideas as to the origin of commonly-used language.

Even common words such as jazz, a term that originated within the lifetime of people still alive at the time of serious attempts to establish its origins, are subject to heated debate. So imagine what must occur with words that are even older.

Often related to cant or rhyming slang, first recorded usage in dictionaries are revised as new documents turn up giving earlier or nuanced usage.

A related issue is what David Crystal refers to as "etymological fallacy". Often occurring when language pundits, objecting to a "new" or different meaning for a word, resort to what they claim is the older meaning, that is the "correct" meaning. Crystal objects to such practices, stating that there is literally no limit to how far back one goes and gives the example of the word nice which can be traced back to Old French, where it meant "silly", and from there to Latin, where it meant "ignorant".

And as Larry Trask points out: "If gay now means 'homosexual'", then that's what it now means, and insisting that it must mean 'cheerful' is likewise a waste of time."

Words and abbreviations
Abbreviations, for some reason, seem to be a favourite among folk etymologists:
 * Cunt
 * Fuck
 * OK
 * Posh