How many letters does the top answer for “people who have been introduced to the mysteries of some field or activity” have?

The most common answer is enlightened (11 letters).

Crossword clue: people who have been introduced to the mysteries of some field or activity

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

enlightened 11 letters wn-def

having knowledge and spiritual insight

initiate 8 letters wn-def

bring into being