Ratifier

(n.) One who, or that which, ratifies; a confirmer.

Thesaurus Entries

Maecenas, abettor, admirer, advocate, aficionado, angel, apologist, approver, backer, buff, certifier, champion, confirmer, cosignatory, cosigner, defender, dependence, encourager, exponent, fan, favorer, friend at court, guarantor, insurer, lover, mainstay, maintainer, notary, notary public, paranymph, partisan, party, patron, promoter, protagonist, ratifier, reliance, second, seconder, sectary, sider, signatory, sponsor, stalwart, standby, subscriber, support, supporter, sustainer, sympathizer, underwriter, upholder, votary, well-wisher