13-Letter Words Matching ___O___U_____

There are 20 13-letter words that match ___O___U_____. 10 are common words, such as ATROCIOUSNESS and FEROCIOUSNESS. A rarer one is REPOSEFULNESS. 11 words contain a doubled letter.

Full list 20

atrociousnessferociousnesshomosexualityincongruitiesincongruouslyinnocuousnesslaboriousnessmalocclusionsmelodiousnessobnoxiousnessarboricultureerroneousnessincongruentlybimolecularlyeffortfulnessfeloniousnesshemodilutionshypopituitaryincongruencesreposefulness

About this list

Words
20 (10 common words)
Common example
atrociousness
Rare example
reposefulness
Doubled letters
11
Ending in S
14

Questions

How many 13-letter words matching ___o___u_____ are there?

20. 10 of them are common words.

What is a common example?

ATROCIOUSNESS is among the common words in this set.