We don't have synonyms for averill yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are averil and averell.
(n) :
Alternative spelling of arval. [(Scotland and Northern England, now rare) A funeral feast or wake at which bread and ale was served, traditional in Scotland, the North of England, and among the Norse.]
(n) :
Alternative spelling of arval. [(Scotland and Northern England, now rare) A funeral feast or wake at which bread and ale was served, traditional in Scotland, the North of England, and among the Norse.]