I do not have as vast a vocabulary as some, but here are some words I've come across so far in a translation of Fyodor Dostoyevsky : Crime and Punishment (Penguin Classics) that I didn't know. These are contained within the first two chapters.

slaked- to cause disintegration of (lime) by treatment with water

erstwhile- former; of times past

jobber- a wholesale merchant, esp. one selling to retailers

nankeen- a firm, durable, yellow or buff fabric, formerly made from a natural-colored Chinese cotton

oleaginous- having the nature or qualities of oil

blackguard- a low, contemptible person; scoundrel

magnanimous- generous in forgiving an insult or injury; free from petty resentfulness or vindictiveness