12-Letter Words Matching ____OF______

There are 21 12-letter words that match ____OF______. 5 are common words, such as MICROFILMING and RETROFITTING. A rarer one is TOPLOFTINESS. In this set, I is the most frequent open letter (19 words). 6 words contain a doubled letter.

Full list 21

microfilmingretrofittingsemiofficialunprofitableunprofitablyhydrofluoriclactoflavinsmicrofinancephotoflashesretroflexionenfeoffmentsmacrofossilsmicrofibrilsmicrofilariamicrofilmersmicrofossilsneurofibrilsneurofibromatibiofibulaetibiofibulastoploftiness

About this list

Words
21 (5 common words)
Common example
microfilming
Rare example
toploftiness
Doubled letters
6
Ending in S
10
Most frequent letter
I (19)

Questions

How many 12-letter words matching ____of______ are there?

21. 5 of them are common words.

What is a common example?

MICROFILMING is among the common words in this set.