10-Letter Words Matching ____F__M__

There are 12 10-letter words that match ____F__M__. 5 are common words, such as MAINFRAMES and PLATFORMED. A rarer one is UNDEFORMED. 2 words contain a doubled letter.

Full list 12

mainframesplatformedreaffirmeduninformedunreformeddoorframesphenforminsemiformalpostformedreinformedslipformedundeformed

About this list

Words
12 (5 common words)
Common example
mainframes
Rare example
undeformed
Doubled letters
2
Ending in S
2

Questions

How many 10-letter words matching ____f__m__ are there?

12. 5 of them are common words.

What is a common example?

MAINFRAMES is among the common words in this set.