15-Letter Words Matching ________AR_____

There are 20 15-letter words that match ________AR_____. 6 are common words, such as BROKENHEARTEDLY and DISSIMILARITIES. A rarer one is TRIANGULARITIES. In this set, I is the most frequent open letter (18 words). 5 words contain a doubled letter.

Full list 20

brokenheartedlydissimilaritiesinvoluntarinessparticularitiesparticularizingunfamiliaritiescountermarchingelectronarcosisextemporarinesstenderheartedlycarcinosarcomasfragmentarinesshyperpolarizingmultipolaritiesovoviviparouslyparticularisingparticularisticreactionaryismsrudimentarinesstriangularities

About this list

Words
20 (6 common words)
Common example
brokenheartedly
Rare example
triangularities
Doubled letters
5
Ending in S
12
Most frequent letter
I (18)

Questions

How many 15-letter words matching ________ar_____ are there?

20. 6 of them are common words.

What is a common example?

BROKENHEARTEDLY is among the common words in this set.