Evangelist

/ɪˈvæn.dʒə.lɪst/

Synonyms

Slang Meanings

A fervent advocate or passionate promoter of any concept.
He's such an evangelist for healthy eating; he can't stop talking about it!
Someone who is excessively enthusiastic about their beliefs or products.
She's a real evangelist for that brand of skincare; she swears by it!