プログレッシブ和英中辞典(第３版)の解説
おすみつき【▲御墨付き】
- 先祖が殿様からいただいたお墨付きです
This is a document [certificate] which one of our ancestors received from his lord. - あなたが本物だと言うのだからお墨付きをいただいたも同然です
The fact that you say it is genuine is the same as receiving an official guarantee.