To be out of something; to have no more of an item on hand — used when supplies or stock are exhausted.
すみません、砂糖が出切ってしまったので買ってきます。
Sorry, we've run out of sugar, so I'll go buy some.
店ではその商品が出切っていて、入荷待ちだった。
That product was sold out at the store and they were waiting for a restock.
当日の参加者が出切ってしまい、資料を追加印刷した。
The attendees exhausted the copies on the day, so we printed additional materials.