This is a famous crux (a passage which invites different interpretations). The two versions of Hamlet published in Shakespeare's lifetime, the First Quarto and the Second Quarto, have "sleaded pollax," which doesn't make good sense. The First Folio (the first collected works of Shakespeare, published after his death by two of his fellow-actors) has "sledded pollax." Edmond Malone (1741 - 1812), famous editor of Shakespeare, emended the "pollax" to "Polacks." However, King Hamlet was at war with the King of Norway, not the Poles, and so some editors emend the phrase to "leaded pole-ax."