Definition of "Polack"

which to him appear'd / To be a preparation 'gainſt the Poleak

c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii], page 260, column 2, line 63

So leuied as before, againſt the Poleak.

c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene ii], page 260, column 2, line 75

First therefore was he employed into Poland, where by Sigismund, the king of Poland and of Suecia, he was received with great magnificence and applause both of the Polack himself and of his people.

1610, Thomas Middleton, “Sir R. Sherley Sent Ambassador, etc.”, in Arthur Henry Bullen, editor, The Works of Thomas Middleton, volume VIII, published 1886, page 307