1. signing the back of a check or other negotiable instrument to transfer ownership or cash it
Usage: finance/banking context
2. publicly supporting or approving someone or something
Usage: common usage
3. writing one's name or signature on a document to confirm or validate it
Usage: legal/formal context

Examples

• She is indorsing the check before depositing it at the bank.
• The mayor is indorsing the new community center project.
• Several prominent scientists are indorsing the climate research findings.
• He was indorsing the contract with his full signature.
• The celebrity is indorsing the new product line in advertisements.
• They are indorsing the candidate for the upcoming election.