14-Letter Words Matching __T__T________

There are 18 14-letter words that match __T__T________. 7 are common words, such as ENTERTAININGLY and ENTERTAINMENTS. A rarer one is WATERTIGHTNESS. 7 words contain a doubled letter.

Full list 18

entertaininglyentertainmentsextortionatelynutritiousnessostentatiouslypotentialitiesuntruthfulnessintentionalityintertwinementmetastaticallypotentiometerscatastrophismscatastrophistscytostaticallydetestablenessoutdatednessespotentiometricwatertightness

About this list

Words
18 (7 common words)
Common example
entertainingly
Rare example
watertightness
Doubled letters
7
Ending in S
10

Questions

How many 14-letter words matching __t__t________ are there?

18. 7 of them are common words.

What is a common example?

ENTERTAININGLY is among the common words in this set.