Many people take a keen interest in keeping a track of difficult words that are formed in the English language. Making a list of interesting words in English language requires a lot of hard thinking, because new words keep getting discovered and added daily. This might sound very obvious but the fear of such difficult words is itself a very long word.

Hippopotomonstrosesquippedaliophobia means fear of pronouncing long words. The list given below has some popular uncommon and difficult words with their definitions.

AbatudeMoney that has been clipped off to make change
AbliguritionSpending a large amount of money on food
AcrasiaLack of self control
AccismusPretend to be not interested when you are really interested in something
AgelastSomeone who never laughs
AgonistarchA coach
AgowiltDreaded fear
BablatriceTalkative woman
BaitheTo agree
BattaExtra pay
BattologistA person who repeats the same thing unnecessarily
BubulcitateCry like a cowboy
BouquinistSomeone who deals in second-hand books
CallipygianIt's an adjective and it means having shapely buttocks
ChadbandSomeone who is hypocritical and unctuous
ChirocracyGovernment by physical force
CatoptromancyForetelling the future
ConcinnousNeat and eloquent
CunctipotentHaving all things
DactylonomyCounting on your fingers
DeipnosophistA good conversationalist at meals
DelitescentSomething which is hidden
DeturpateTo make something ugly
DiazingiberA kind of ginger candy
DigitigradientTo walk on your toes
DrawcansirA person who kills both his friends and foes
ElaqueateTo get free from entanglements
EncomiumsFormal praises
ErgophobicA person who fears work
EquivoqueSomething that has been given a similar name as something else
ErinaceousPeople with bristly manners
ExpergefactionWaking up
FaginA person who trains other people in crime
FestuceousLike a straw
FinnimbrunA trinket
GaberlunzieA beggar
GadzookeryUse of archaic words
GallinipperA large mosquito
GeoponicAnything related to farming
GlaikeryFoolish conduct
GongoozlerAn idle person or rubbernecker
HalieuticRelates to fishing
HarbargeryA place where you find entertainment
HeimgangerA person who always stays at home
HeptamerousSomething that has 7 parts
Hiccius DocciusA magical phrase
IatralipticA doctor who cures ailments using lotion or cream
IctericalColored with yellow
IllatrationBarking at someone
ImpeticosA word included in a dialog to make its presenter look like a fool
InfelicificFemale investigator
InsangelousEqual to the angels
JaculiferousTo have prickles
JectigationTrembling movement
KakistocracyA government which is run by its bad citizens
KyriolexyProper speaking
LaetificantSomething which acts as an anti-depressant
LudibriousTo be the center of a joke
MagirologyThe science of cooking
MesonoxianRelates to midnight
MoriologistA person who has been hired to mourn at a funeral
MotatoriousIn continuous motion
MututatialSomething which is borrowed
NabocklishLeaving something alone
NaufragateTo destroy something
NimfadaroA male who is well dressed and popular with women
NudiustertianThe day before yesterday
ObambulateWander about
OmbrifugeShelter from rain
OoglificationTo replace a "oo" sound with another vowel to make the word slang
PassiuncleA petty passion
PercibrateTo move fast
PhilopolemicalLove to fight
PyknicA person who has a round belly and head and who has a tendency to put on weight
QuadragenarianA person who is 40, but doesn't make a big deal out of it
RampallionA Scoundrel
RelexificationReplacing a word or phrase in one language with a word or phrase from another language which corresponds to it
SanquinolencyAddicted to bloodshed
ScrimshandrixA woman who makes a scrimshow
SqunitifegoA person who squints a lot
TegestologyCollecting beer mats
Terpsichoreanrelated to dancing
TragematopolistCandy Seller
TristichousArranged in three rows or ranks
UbiquarianA person who goes everywhere
UnwelewableTo be unfadeable
VerticordiousTo turn the heart away from evil
ViscerotonicAn easygoing personality
WeddingerA guest at a wedding
XanthippeA woman with a bad temper
XylopyrographyAn art of creating wood designs by using a hot poker
YesterangSomething that was caught yesterday
ZabernismThe abuse of authority

Long Complicated Words

The list of complex words which are long and difficult to pronounce is endless. For people who love knowing such confusing words, here are some more examples.

Floccinaucinihilipiiification: Estimation that something is valueless.

Hippopotomonstrosesquipedalian: Means a very long phrase.

Honorificabilitudinitatibus: Honorableness.

Tetramethyldiaminobenzhydrylphosphinous: A type of acid.

Dimethyl­amido­phenyl­dimethyl­pyrazolone: A checmical term.

Taumata­whakatangihanga­koauau­o­tamatea­turi­pukakapiki­maunga­horo­nuku­pokai­whenua­kitanatahu: It is a hill in New Zealand.

Gorsafawddachaidraigodanheddogleddolonpenrhynareurdraethceredigion: A town in Wales.

Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch: A town in Northern Wales.

Chargogagogmanchargogagogcharbunagungamog: Another name for lake Webster in Massachusetts.

So these are some of the most difficult words in the English language that I could find for you people. If you want to find some more, you can search on the Internet and the various dictionaries. Have I missed out on any long cool words to say? I must have, so do give your valuable comments and suggestions.