Laertes is the primary foil to Hamlet in the play. In many ways he is Hamlet’s opposite, and these opposites serve to underline and intensify Hamlet’s own traits. Whereas Hamlet is contemplative, introspective, and moody, Laertes is forceful, driven, and inclined to action, often without thinking through the consequences.
In many ways, the two men are similar: they are of similar age, and both lose their fathers to murder during the play. Both become obsessed with the idea of getting revenge. But while Hamlet’s response to the vengeance urge is to question it obsessively, Laertes’ response is to act, no matter the cost. Both are also deeply interested in questions of moral honor, albeit in different ways. Hamlet’s interest takes the form of philosophical speculation on the meaning of honor, while Laertes’ interest surfaces in his actions, such as in giving Hamlet a chance to save his own life by trying to kill him in a duel, rather than simply poisoning him or sneaking up on him.