exponent (n.)

• abettor
• admirer
• advocate
• aficionado
• alternate
• angel
• annotator
• apologist
• attorney
• backer
• backup
• booster
• buff
• case
• champion
• cicerone
• commentator
• critic
• cryptanalyst
• cryptographer
• cryptologist
• decoder
• defender
• demonstration
• demonstrator
• dependence
• deputy
• dragoman
• dummy
• editor
• emblem
• embodiment
• endorser
• example
• exegete
• exemplar
• exemplification
• explanation
• expositor
• expounder
• fan
• figurehead
• go-between
• guide
• illustration
• instance
• interpreter
• lexicographer
• lieutenant
• locum
• lover
• mainstay
• maintainer
• partisan
• patron
• pleader
• procurator
• promoter
• proponent
• protagonist
• proxy
• reliance
• representation
• representative
• scholiast
• second
• secondary
• seconder
• sectary
• sider
• specimen
• sponsor
• stalwart
• stand-in
• standby
• substitute
• support
• supporter
• surrogate
• sustainer
• symbol
• sympathizer
• translator
• type
• typification
• understudy
• upholder
• vicar
• vice
• vicegerent
• votary
• well-wisher