我想問會計上 written off的意思?

Written-off may refer to either an accounting write-off or an income tax write-off.
Accounting:
In business accounting, the term write-off is used to refer to an investment (such as a purchase of salable goods) for which a return on the investment is now impossible or infeasible. The item's potential return is thus canceled and removed from ("written off") the business's balance sheet. Common write-offs in retail include spoiled and damaged goods.

Written off : 一筆勾銷