> the word whose usage is considered so offensive that it has caused the decline of its unfortunate near-homophone ‘niggardly’ That's not exactly a unique phenomenon. For example, it's how "rabbit" replaced "coney".
In Spanish conejo (rhymes with coney) is rabbit. Interesting how we’re still slowly loosing cognates from our shared latin roots. Edit: I may be assuming an incorrect pronunciation of coney. Even as a native speaker English sucks.
As an aside, Spain itself was named after rabbits, which I find hilarious: http://www.ctspanish.com/rabbits.htm