rejected manuscript
A manuscript that has been rejected for publication, typically by a publisher or editor.
His novel became a rejected manuscript.
没書の山を前に、作家はため息をついた。
Facing a pile of rejected manuscripts, the writer sighed.
Compound of 没 (rejection, sinking) and 書 (writing, document). The exact historical derivation is uncertain, but the term is straightforwardly understood as 'rejected writing'.