The word "impeach" is much in the news of late.  It is of Anglo-French origin and originally meant to hinder or impede.  As discussed in this post, the first English impeachment in Parliament dates from the fourteenth century. 

Two centuries later, William Shakespeare used the verb "impeach" 11 times in 8 plays (Comedy of Errors, Henry IV (part 1), Henry VI (part 3), King John, Merchant of Venice, Midsummer Night's Dream, Richard II, and Romeo & Juliet).  The noun, "impeachment", appears in only two of his plays (Henry V and Two Gentlemen of Verona).

Shakespeare employs the original meaning of "impeach" in this passage from Merchant of Venice and incidentally provides an explanation for why it is in the state's interest that judges follow the law:

"The duke cannot deny the course of law:
For the commodity that strangers have
With us in Venice, if it be denied,
Will much impeach the justice of his state;
Since that the trade and profit of the city
Consisteth of all nations."

Act III, Scene 3.