noun

the action of endorsing someone or something.

the issue of full independence received overwhelming endorsement

support,backing,approval,seal of approval,agreement,acceptance,recommendation,advocacy,championship,patronage,affirmation,confirmation,authorization,authentication,ratification,sanction,warrant,validation,licence,rubber stamp,the nod,the thumbs up,the OK,countersigning,signing on the back,autographing,initialling,inscribing,superscribing,witnessing,underwriting