Words that include 'efi'

What is the longest word you can assemble from words with 'efi' in them?
'Nonbeneficialness' is the largest word that Dictionarypedia could locate, consisting of 17 characters

What is the max number of words you could construct from this combination of letters?
On this list of words with 'efi' in them, there are 645 entries that can be selected.

In Scrabble, what's the best score you can get from words that include 'efi'?
As there are an overwhelming 645 entries, your best option is to choose 'junefish' scoring 21 points.

Which word on this page is the most common?
When it comes to well-known words, there's 'benefit' which ranks as the 2907^th most popular word.

Which is the most unusual word with 'efi' in them?
Undoubtedly one of the most peculiar words from this page is 'veneficious'. 'Veneficious' is defined as "Acting by poison; used in poisoning or in sorcery. [Obs.] "An old veneficious practice." Sir T. Browne. -- Ven`e*fi"cious*ly, adv. [Obs.]", according to the English dictionary.