Maven

Recently a friend was called a maven. This was a compliment; a maven is a person of knowledge, understanding and wisdom (sounds a bit like something out of the Kabbalah קַבָּלָה‎, but that’s a bit over the top; more to the point the word has almost totally lost its Jewish roots in modern English)

In network theory and sociology, a maven is someone who has a disproportionate influence on other members of the network. The role of mavens in propagating knowledge and preferences has been established in various domains, from politics to social trends.

Oddly the word is fairly new to English. The word comes from the Yiddish meyvn and Hebrew mevin (מבֿין), with the same meaning, which in turn derives from the Hebrew binah, meaning understanding. It was first recorded in English around 1952, and popularized in the 1960s by a series of commercials for Vita Herring created by Martin Solow, featuring "The Beloved Herring Maven." The “Beloved Herring Maven“ ran in radio ads from 1964-1968.

Since the 1980s it has become more common since William Safire adapted it to describe himself as "the language maven". The word is mainly confined to American English, but had not yet appeared with the publication of the 1976 edition of Webster's Third New International Dictionary.