John Hancock OK accept acceptance accredit affirm affirmance affirmation amen approbation approval approve authenticate authentication authorization authorize autograph certification certify confirm confirmation cosign countersign countersignature endorse endorsement give permission give the go-ahead give the imprimatur give thumbs up go-ahead green light imprimatur initial nod notarization notarize okay pass pass on pass upon permission permit ratification ratify sanction say amen to seal second sigil sign sign and seal signature signet stamp stamp of approval subscribe to subscription support swear and affirm swear to the nod undersign underwrite validate validation visa vise warrant