13-Letter Words Matching __EF_________

There are 16 13-letter words that match __EF_________. 5 are common words, such as INEFFECTIVELY and INEFFECTUALLY. A rarer one is PREFORMULATES. In this set, I is the most frequent open letter (14 words). 7 words contain a doubled letter.

Full list 16

ineffectivelyineffectuallyinefficientlyprefabricatedprefabricatesinefficaciousprefigurationprefigurativeprefigurementdieffenbachiaineffablenesspreferabilitypreformationspreformattingpreformulatedpreformulates

About this list

Words
16 (5 common words)
Common example
ineffectively
Rare example
preformulates
Doubled letters
7
Ending in S
5
Most frequent letter
I (14)

Questions

How many 13-letter words matching __ef_________ are there?

16. 5 of them are common words.

What is a common example?

INEFFECTIVELY is among the common words in this set.