To do (someone) a service or favour (hence, originally, creating an obligation).
To be indebted to someone.
To constrain someone by force or by social, moral or legal means.
To decline (a request or demand).
To decline a request or demand, forbear; to withhold permission.
To melt again.
To throw back, or cause to keep back (as the centre, a wing, or a flank), out of the regular alignment when troops are about to engage the enemy.
Discarded, rejected.
Collectively, items or material that have been discarded; rubbish, garbage.