endorser

transitive verb endorsed, endorsing

1. to write on the back of (a document); specif.,
   1. to sign (one's name) as payee on the back of (a check, money order, etc.)
   2. to make (a check, etc.) payable to another person by thus signing one's name and specifying the payee
2. to write a note, title, etc. on (a document)
3. 1. to give approval to; support; sanction: to endorse a candidate
   2. to state, as in an advertisement, that one approves of (a product, service, etc.), often in return for a fee

Origin: altered (after L) < ME endosen < OFr endosser < ML indorsare < L in, on, upon + dorsum, the back