The word 'hamartia' is a transliteration of the ancient Greek word ἁμαρτία (hamartia), which is one of two nouns - the other is ἁμάρτημα (hamartema) - from the verb ἁμαρτάνειν (hamartanein). The original meaning of hamartanein is 'to miss the mark' - in Homer, e.g., the word is used in this sense of a thrown spear which fails to hit or falls short of its target - but the verb comes to be used more generally of someone who fails to achieve his or her purpose or goes wrong and, with a sense of moral disapprobation, of someone who does wrong or sins. The nouns hamartia and hamartema reflect this range of meanings: they can mean 'mistake', 'fault', 'flaw', or 'sin', and differ in their use only insofar as hamartema tends to refer to the mistaken or sinful action, while hamartia tends to refer to the mistaken belief or sinful desire which leads to the action.
In English the word 'hamartia' is used in two very different contexts: in literary discussions, particularly of tragic drama, and in theological discussions of the Christian doctrine of sin.
Hamartia and tragic drama
The use of the word 'hamartia' in this context derives from the discussion of tragedy by the Greek philosopher Aristotle in his Poetics. Aristotle argues there, in ch. 13, that in the best kind of tragic plot the protagonist is a person who 'is in an intermediate position, who is not outstandingly virtuous or just, and who meets with misfortune not because of any wickedness or vice, but because of some hamartia' (1453a7-10). The interpretation of 'hamartia' in this passage has been much disputed, but a careful reading of the chapter strongly suggests that it should be taken to mean 'mistake'. Hence Aristotle's view is that in the best plots the misfortunes of the tragic protagonist result from some mistake that he makes, a mistake for which he cannot be blamed and which need not point to any fault or flaw in his character. Aristotle's preferred example of a tragic protagonist, the Oedipus of Sophocles' Oedipus Tyrannus, cannot be blamed for the mistaken beliefs about his parentage which lead him unknowingly to kill his father and marry his mother, nor do these false beliefs seem to point to any flaw in his character. Moreover, a plot in which the protagonist's tragic misfortunes result from a simple mistake and are to this extent 'undeserved', is surely more likely achieve what in Aristotle's view is the purpose of tragedy, i.e., to arouse pity and fear in the audience, than one in which the tragic outcome is the result of a flaw in the protagonist's character and is to this extent 'deserved'. (See further D.W. Lucas, Aristotle: Poetics, Oxford: Clarendon Press, 1968.)
However, some commentators have taken hamartia in Poetics ch. 13 to mean 'flaw' or 'weakness of character' and have attributed to Aristotle the view that the tragic protagonist has some fault or flaw of character and that it is this fault or flaw, not a simple mistake, which leads to his or her tragic misfortunes. This theory, whether or not it would have been endorsed by Aristotle, has gained wide acceptance - not least because of its successful application to the tragedies of Shakespeare. The Shakespeareean tragic protagonist, according to this interpretation, is a good man whose tragic end results from a flaw in his character - in Macbeth's case ambition, in Othello's jealousy, and so on.
Hamartia and sin
The word hamartia occurs frequently in the Greek New Testament, and the Authorised Version regularly translates it as 'sin' (e.g., John, ch. 8, v. 46). The verb hamartanein, with the meaning 'to sin', is also common.
The original meaning of hamartanein, i.e., 'to fall short of a target', seems to have been in the mind of the apostle Paul when he wrote in his Epistle to the Romans (ch. 3, v. 23) that 'all have sinned and come short of the glory of God'. This original meaning is also reflected in the many Christian accounts of sin as essentially a kind of falling short. Self-evidently, as the 'classical doctrine' of sin insists, the person who sins, i.e., fails to do what is required by God's commandments, falls short of a standard, but the conception of sin as a falling short has been elaborated in other, less obvious ways. The so called 'process theologians', for example, have argued that sin is essentially a falling short of one's potential as a human being, while others such as the German theologian Paul Tillich (1886-1965) have held that the state of sin is essentially a state of alienation from God and thus a falling short of the relationship which ought ideally to exist between human beings and God.