Proper words include: book, boom, boon, boor, boot; cook, cool, coop, coot; doom, door; food, fool, foot; good, goon; hood, hook, hoop, hoot; look, loom, loop, loot; mood, moon, moot; noon; pool, poop, poor; rood, roof, rook, room, root; soon, soot; took, tool, toot; wood, woof, wool. There are also some informal or slang words, like boob, coon and toon.
ally
Seen been book look took tool seek meek
Some six letter words with FF in the middle are:wafflebafflebufferduffermufflepifflesufferduffelpuffindiffer
addassallillofferrbeeseefeepeeteeweezooboocoogoomootoooddebb
Jeep
Some six letter words that end in double letters:accessacrossapogeebamboobefallboo booboohoobungeebypasscaresscoffeecouleecuckoodecreedegreeduressegressembossenrollentreeexcessgoateeharassHawaiilayofflycheemorassmuumuupayoffpeeweepizazzrebuffrecallrecessrefillremissripoffrunoffscrollscruffsetteeshrillsoireesquallstressstrolltarifftattoothrilltoffeetoupeeunlessvoodoo
bookboombootcookcoolcoopcootdoorgoodgoongoophoodhookhooplookloonloomlooplootmoodmoonmoornookpoofpoorpoolrootrookroofroomsoonsoottoottooktoolwoodwoolwoofzoom
Some six letter words with FF in the middle are:wafflebafflebufferduffermufflepifflesufferduffelpuffindiffer
addassallillofferrbeeseefeepeeteeweezooboocoogoomootoooddebb
Some six letter words with OOS in the middle:IgloosKazoosWazoosYahoos
Eel
buffcuffmuffpuffballbellbillbullcallcellmallmillmullnullpillpullrollsillselltilltelltallwallwellwillbassbosscussfusshisskisslessmessmissmassmosslosspasssasstossmuttmittbuttdollfallfellfillfull
sully, sunny
Ill and inn.
Some words that have the letters ME twice in the middle are:amendmentcommencementdismembermentmeantimemeasurementmementomerrimentmesmerisemetronomesometimesummertime
Jeep
Some six letter words that end in double letters:accessacrossapogeebamboobefallboo booboohoobungeebypasscaresscoffeecouleecuckoodecreedegreeduressegressembossenrollentreeexcessgoateeharassHawaiilayofflycheemorassmuumuupayoffpeeweepizazzrebuffrecallrecessrefillremissripoffrunoffscrollscruffsetteeshrillsoireesquallstressstrolltarifftattoothrilltoffeetoupeeunlessvoodoo
bookboombootcookcoolcoopcootdoorgoodgoongoophoodhookhooplookloonloomlooplootmoodmoonmoornookpoofpoorpoolrootrookroofroomsoonsoottoottooktoolwoodwoolwoofzoom
impress mastiff regress