100 Difficult Words to Build an Excellent Vocabulary

1) puissant- influential, powerful, important

2) encomium- a speech or piece of writing that praises someone or something highly-- like a eulogy, panegyric, accolade, tribute, etc.

3) lusus naturæ-- a person or animal that is markedly unusual or deformed; a freak or monstrosity

4) conceit- a fanciful expression or elaborate metaphor. For example, "the idea of the wind's singing is a prime romantic conceit". It can also be, an artistic device: "the director's brilliant conceit was to film it all in black and white". Or, a fanciful notion: "he was alarmed by the widespread conceit that he spent most of the 1980's drunk".

5) effluvium (singular), effluvia (plural)- an unpleasant or harmful odor, secretion, or discharge. "The swamp's effluvia".

6) chimera- a thing that is hoped or wished for but in fact is impossible to achieve. For example: "the economic sovereignty you claim to defend is a chimera" or "is this great love of hers merely a chimera?". In Greek mythology, the Chimera is a fire-breathing female monster with a lion's body, a goat's body, and a serpent's tale.

7) peccant, adj-- having committed a fault or sin; sinful; offending; violating a rule, principle, or established practice; faulty or wrong. "The minister delivered a stern sermon warning peccant parishioners of the punishments that awaited them in the afterlife." Or: diseased or causing disease.

8) occiput, noun-- the back portion of the head or skull

9) expostulate-- 

execrable

cant
indemnity

seminary

rapine

repletion

parity

restive

pastern

exhort

descanting

lissome

bailiwick

cadre

frisson

farinaceous

myrmidon

suborn

excrescence

incipient

collation

portmanteau

prolix

discursive

episcopacy

archiepiscopacy

effulgent

fasces

argosy

quiescence

unctuous

cabalistic
cabala

heliotropic

sedulous

anathema

pertinacity

munificent/munificence

ebullition

equanimity

privity

empiric

torpid

tarn

tenuity

abeyance

concision

cataleptical

distempered

extirpate

educe

phantasmagoria

pinion

collocate

treacle/trestle

vagary

casement

incubus

meerschaum

orbicular

renumerative

abrogation

avocation

cistern

inchoate

parfleche

halcyon

supernumerary

immanence

peculation

blandishment

bonhomie

asseveration

celerity

salient

salutary

imputation

parsimony

mendicancy

meretricious

oblation

quid pro quo

invocation

indigent

ombudsman

qua

epistemological

cognizance

metaphysical

dialectical

ineffable

dogma

ersatz

expropriating

chimera

iniquity

determinism

atavistic

coppice
paean- song of praise or triumph, example: "the bards sang a paean to the war".

pannier + dérailleur

political and career radiation

quadrangle

erudite

suzerain
panegyric- public speech praising someone or something

genuflect

solipsism

ailurophobic

monolithic

prelature

offertory

vilify

esplanade

canonization

apropos

gibbous

caparisoned

comity

effuse

melange

dolce affettuoso
eructation
tenesmus
purposive
burlesque
trope
adjudicate
sprezzatura