Like I said the question is flawed. The correct question is the word with 3 sets of double letters in it back to back.
coffee / toffee are two most here probably have the former every day and the latter sometimes.
Keep in mind a dictionary also often has common "non-English" words as well.
Bookkeeper opens up bookkeeping.
[edit] ignore the below...I have been drinking and got carried away with double letter words.
Mississippi should be in the head's of most American's.
You also have aggressiveness.
Tallahassee for us Floridian's.
Heedlessness.
Committee.
I think I have successfully answered your question.
[/edit]
sweet-toothed is in the dictionary.
The correct question if bookkeeper is the only answer is "What root word in the English Dictionary is the only word to have three sets of consecutive double letters in it back to back?
Nice edit. Sweet-toothed is obviously two words.
But I'll give you this - you find your way around those big words quite well.