What do the following words have in common?

1. FAT
2. ROUTE
3. IMAGE
4. MUTE
5. VILLA
6. SPIRE
7. MISTER
8. BULLET
9. FANCIER
10. CONTENT

HINT:
The same two letters, though not in the same position, will change each word into a new one.

Answer:

The letters IN can precede, follow, or be inserted into each word to produce new words:

1. FAINT
2. ROUTINE
3. IMAGINE
4. MINUTE
5. VILLAIN
6. INSPIRE
7. MINISTER
8. BULLETIN
9. FINANCIER
10. CONTINENT

Credit: Will Shortz
The Puzzlemaster Presents
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