"Bosky" is usually used to describe something densely wooded or covered in trees (like a "bosky grove").
If you're looking for a type of fabric, you might be thinking of something similar sounding, like:
* Brocade: A rich, woven fabric with raised designs.
* Batik: A fabric with wax-resist dyeing techniques.
* Bohemian: A style of fabric that often features earthy colors and patterns.
Please clarify if you can remember more details about the fabric, or if you heard it in a specific context.