A real word is trekker, a slang word is likker.
Bookkeeper and jackknife are words. They contain the letters kk.
These letters can be rearranged to spell the country Germany. The next longest words from these letters include German and manger.
Words with IE in the middle:dieddiesdietliedliespierpiespriesttiedtierties
sauce
Some six letter words with FF in the middle are:wafflebafflebufferduffermufflepifflesufferduffelpuffindiffer
Bookkeeper and jackknife are words. They contain the letters kk.
These letters can be rearranged to spell the country Germany. The next longest words from these letters include German and manger.
chordsscoresscornsshoresstoresstorksstormsswordsthorns
Words with IE in the middle:dieddiesdietliedliespierpiespriesttiedtierties
buckknife
sauce
OMELETTE
"Double letters" means two in a row, like tt in "letter" or oo, kk, and ee in "bookkeeper".
Words with "te" in the middle:litersmeters
Some six letter words with FF in the middle are:wafflebafflebufferduffermufflepifflesufferduffelpuffindiffer
Cobra
Some words that have the letters ME twice in the middle are:amendmentcommencementdismembermentmeantimemeasurementmementomerrimentmesmerisemetronomesometimesummertime