Based on ACT 1

If Macbeth is indecisive, Lady Macbeth is just the opposite—a character with such a single vision and drive for advancement that she brings about her own demise. And yet her very ruthlessness brings about another form of ambiguity, for in swearing to help Macbeth realize the Weird Sisters' prophecy, she must cast off her femininity. In a speech at the beginning of Scene 5, she calls on the spirits of the air to take away her womanhood:

Come you spirits
That tend on mortal thoughts, unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty. Make thick my blood,
Stop up th'access and passage to remorse,
That no compunctious visitings of nature
Shake my fell purpose, nor keep peace between
Th'effect and it. (I v 38-45)

Lady Macbeth sees "remorse" as one of the names for feminine compassion—of which she must rid herself. Thus she must be "unsexed." This does not mean, however, that in rejecting her femininity she becomes manly. Instead, she becomes a woman devoid of the sexual characteristics and sentimentality that make her a woman. She becomes entirely unnatural and inhuman. Like the supernatural Weird Sisters with their beards, Lady Macbeth becomes something that does not fit into the natural world.

For example, in Scene Seven, Macbeth tells his wife that he "will proceed no further in this business" (31). But Lady Macbeth taunts him for his fears and ambivalence, telling him he will only be a man when he carries out the murder. She states that she herself would go so far as to take her own nursing baby and dash its brains if necessary. She counsels him to "screw [his] courage to the sticking place" and details the way they will murder the king (60). They will wait until he falls asleep, she says, and thereafter intoxicate his bodyguards with drink. This will allow them to murder Duncan and lay the blame on the two drunken bodyguards. Macbeth is astonished by her cruelty but resigns to follow through with her plans.