(n.) a field created by clearing a forest
An area of land that is busky, or bosky, is covered in thickets and low-lying vegetation. Busk in this context is just an alteration of bush, in recorded use in English since the 1500s. (Bush, meanwhile, is one of those words that’s so ancient it’s older than the English language itself.) A ‘busky’ clearing created by felling an area of woodland, then, is a buskyley.
Or at least it is according to the English Dialect Dictionary, which has traced this particular regionalism back to the early 1800s.
The ‘–ley’ part here is a form of lea or leah, an Old English word for a forest clearing—whether manmade or natural—or any larger, open tract of land. It’s a word probably better known today as a so-called place name element—a unit of meaningful information fossilized inside the names we find on our maps.
It’s from there that most of our place names ending in –ley, –ly, or even –leigh have derived—so the –ley you find at the end of buskyley is, via centuries of etymological development, the same you find at the end of places like Barnsley, Keighley, Beverley and Henley.