To declare one's public approval or support of something or someone. The celebrity decided to endorse the new product, boosting its sales significantly.
To sign a check or bill of exchange on the back to make it payable to someone other than the stated payee or to accept responsibility for paying it. She had to endorse the check before depositing it into her account.
To write one's signature on the back of a document, especially a check, to indicate approval or transfer of rights. He endorsed the document to confirm his agreement with the terms.
To give formal or official approval to; to sanction or support (a plan, proposal, statement, etc.). The board unanimously endorsed the new strategic plan.
In British usage, to record an offence or information on (an official document such as a driving licence). His licence was endorsed with three penalty points for speeding.