11-Letter Words Matching _____UM____

There are 16 11-letter words that match _____UM____. 2 are common words, such as INSTRUMENTS and INTEGUMENTS. A rarer one is REARGUMENTS. In this set, I is the most frequent open letter (13 words). 4 words contain a doubled letter.

Full list 16

instrumentsintegumentsaltocumulusgoodhumoredshowjumpingthingumabobthingumajigthingummiesantidumpingantitumoralhoodlumismsnonaluminumouttrumpingoverpumpingquadrumvirsrearguments

About this list

Words
16 (2 common words)
Common example
instruments
Rare example
rearguments
Doubled letters
4
Ending in S
7
Most frequent letter
I (13)

Questions

How many 11-letter words matching _____um____ are there?

16. 2 of them are common words.

What is a common example?

INSTRUMENTS is among the common words in this set.