This list does not include words I look up to make sure I have the correct use or spelling — that list would be far too embarrassing to publish.
abstruse
chthonic
moldering
marmite
vitreous humor
whist
gerontocratic
peripatetic
eschatological
obdurate
metonym
incipient
koan
peripatetic is one of the best words ever!
Abstruse always reminds me of You've Got Mail