Explanation:
Equivocation is the use of ambiguous language to conceal the truth or to avoid committing oneself. This is used quite often in Shakespeare's play, mostly with Macbeth and Lady Macbeth when they try to hide the fact the they plan to kill King Duncan. In Act 1 Scene 7, Macbeth says, "False face must hide what the false heart doth know."
In Act 2 Scene 3, when Macduff finds the bloody corpse of King Duncan, the porter that is still drunk from drinking in the night says that he is the porter of hell and says "equivocator, that could swear in both the scales against either scale". This line is considered a reference to the book "A Treatise of Equivocation". The book was about how Catholics dealt with dangerous questions from Protestant inquisitors. If the Catholics told the Protestants that they were Catholics they would get in serious trouble and it would be a sin against God. So they decided to equivocate. The Catholic equivocators would tell the Protestants what they wanted to hear, but God would know that they would be telling the truth. This in another equivocation but doesn't necessary make it a good thing.
When Macbeth visits the witches for the apparition, the witches that are working for the devil, equivocate all their apparitions. The first one says that "armed Head", Macbeth thinks that it means beware Macduff but it actually is that Macduff in armor, head of the army will defeat Macbeth and chop his head off. The next apparition, says that, Macbeth must "Be bloody, bold, and resolute; laugh to scorn / The power of man, for none of woman born / Shall harm Macbeth". Macbeth then fears no one because everyone is born of a woman but Macduff isn't. He was ripped from his mother's womb and we find out the casarean doesn't count as born from a woman. The final apparition, says "child crowned, with tree in hand and assures Macbeth that, "Macbeth shall never vanquish'd be until / Great Birnam wood to high Dunsinane hill / Shall come against him". The child crowned means that the child of Duncan, Malcolm, will become king which happens in the end of the play. Macbeth doesn't believe that the wood and trees can move until we find out that the army uses the trees as camouflage and are able to move it.
