13-Letter Words Matching __FI_________

There are 12 13-letter words that match __FI_________. 6 are common words, such as AFFIRMATIVELY and EFFICACIOUSLY. A rarer one is INFIBULATIONS. In this set, I is the most frequent open letter (11 words). 7 words contain a doubled letter.

Full list 12

affirmativelyefficaciouslyinfiltrationsinfinitesimalofficeholdersofficiousnessdefibrillatordefibrillateddefibrillatesdefibrinatingdefibrinationinfibulations

About this list

Words
12 (6 common words)
Common example
affirmatively
Rare example
infibulations
Doubled letters
7
Ending in S
5
Most frequent letter
I (11)

Questions

How many 13-letter words matching __fi_________ are there?

12. 6 of them are common words.

What is a common example?

AFFIRMATIVELY is among the common words in this set.