11-Letter Words Matching ____T_F____

There are 20 11-letter words that match ____T_F____. 15 are common words, such as BEAUTIFIERS and BEAUTIFULLY. A rarer one is UNDUTIFULLY. In this set, I is the most frequent open letter (19 words). 7 words contain a doubled letter.

Full list 20

beautifiersbeautifullybeautifyingbountifullyfructifyinghealthfullyidentifiersidentifyingplentifullyprettifyingquantifiersquantifyingsanctifyingstratifyingstultifyingbeautifulerprettifiersrenotifyingsanctifiersundutifully

About this list

Words
20 (15 common words)
Common example
beautifiers
Rare example
undutifully
Doubled letters
7
Ending in S
5
Most frequent letter
I (19)

Questions

How many 11-letter words matching ____t_f____ are there?

20. 15 of them are common words.

What is a common example?

BEAUTIFIERS is among the common words in this set.