(n.) One who explains or expounds; a translator\; especially, a person who translates orally between two parties.

allegorist annotator artist artiste cicerone clarifier commentator concert artist critic cryptanalyst cryptographer cryptologist decoder definer demonstrator demythologizer diaskeuast dragoman editor emendator emender euhemerist executant exegesist exegete exegetist explainer explicator exponent expositor expounder go-between guide hermeneut lexicographer maestro metaphrast minstrel minstrelsy music maker musician oneirocritic paraphrast performer player scholiast soloist textual critic translator tunester virtuosa virtuoso