13-Letter Words Matching ____I__U_____

There are 21 13-letter words that match ____I__U_____. 10 are common words, such as DECEITFULNESS and DISTINGUISHED. A rarer one is POSTINAUGURAL. 10 words contain a doubled letter.

Full list 21

deceitfulnessdistinguisheddistinguishesgallimaufriesmellifluouslyoverindulgentoverindulgingpromiscuitiespromiscuouslypropinquitiesglutinousnessunanimousnessveggieburgerscallithumpianmellifluentlynondiffusiblenondiscursivenondisruptivenonlinguisticoverissuancespostinaugural

About this list

Words
21 (10 common words)
Common example
deceitfulness
Rare example
postinaugural
Doubled letters
10
Ending in S
9

Questions

How many 13-letter words matching ____i__u_____ are there?

21. 10 of them are common words.

What is a common example?

DECEITFULNESS is among the common words in this set.