In Shakespeare's Macbeth, Macbeth and his wife Lady Macbeth are both examples of tragic heroes who possess a tragic flaw. According to Webster's dictionary, a tragic flaw is defined as "a flaw in character that brings about the downfall of the hero of a tragedy." Macbeth held within his character the flaw of ambition, as well as moral weakness and selective perception, which all eventually contributed to his untimely death. In Lady Macbeth's case, the main fault that brought about her destruction and final suicide was greed, along with an ignorance and/or repression of the emotions that contradicted this desire. Both characters began in high positions and, throughout the play, accumulated losses caused by their own weaknesses in personality.
There is already evidence of Macbeth's inborn ambition in the beginning of the play in the fact that he holds a high position as the Thane of Glamis and is an acclaimed general in the army, things which are typically not acquired without the presence of a desire for them.
Hence, the term ambition can be applied to this want of greatness. There is further evidence of this trait in his reaction to the first prophecies of the three witches. While many others would have avoided talking to witches for their obvious affiliation with evil, Macbeth hears what they have to say and responds with curiosity, saying, "Stay, you imperfect speakers. Tell me more." (I.iii.73). This is also an example of his other flaw, which is that he hears what is beneficial to his ulterior motives.
At this point in the play, Macbeth's ambition is in a controlled state and is harming neither him nor others. In the next scene, however, there is indication of a slight overstepping of boundaries when King Duncan gives Macbeth the title of Thane of Cawdor...