Okonkwo dedicates himself to being as masculine as possible, and through his rise to become a powerful man of his tribe and subsequent fall both within the tribe and in the eyes of his son Nwoye, the novel explores the idea of masculinity. Okonkwo believes in traditional gender roles, and it pains him that his son Nwoye is not more aggressive like he is. As a result, it's revealing that he expresses the wish that his daughter Ezinma were a boy—from this we know how fond he is of her. Additionally, in a meeting towards the very beginning of the book, Okonkwo insults a man without title by calling him a woman, demonstrating how much masculinity is valued when ranking those in Umuofia society. Ultimately, though, Okonkwo's adherence to masculinity and aggression leads to his fall in society—he becomes brittle and unable to bend with the changes taking place in his clan. In keeping with this principle of masculinity, Okonkwo forces himself to kill his own surrogate son, murder the white man against his better judgment, and hang himself before a punishment can be imposed by others. Okonkwo's aggression makes him weak in the end—it leaves him with no room to maneuver against the more subtle ways of the white man.
Nwoye struggles with this idea of masculinity, as he wants to please his father by being aggressive and traditional, but ultimately, he's repelled by the violence in Umuofia rituals and joins the Christians. Nwoye's departure can also be linked to this idea from Okonkwo's uncle, Uchendu, after the family is exiled from Umuofia: “'It's true that a child belongs to its father. But when a father beats his child, it seeks sympathy in its mother's hut.'” Likewise, after being beaten by his father, Nwoye leaves to seek solace in the more feminine and seemingly gentle Christian religion.
Masculinity Quotes in Things Fall Apart
…[Okonkwo] was not afraid of war. He was a man of action, a man of war. Unlike his father he could stand the look of blood. In Umuofia's latest war he was the first to bring home a human head.
Even as a little boy he had resented his father's failure and weakness, and even now he still remembered how he had suffered when a playmate had told him that his father was agbala. That was how Okonkwo first came to know that agbala was not only another name for a woman, it could also mean a man who had taken no title. And so Okonkwo was ruled by one passion – to hate everything that his father Unoka had loved. One of those things was gentleness and another was idleness.
Okonkwo did as the priest said. He also took with him a pot of palm-wine. Inwardly, he was repentant. But he was not the man to go about telling his neighbors that he was in error. And so people said he had no respect for the gods of the clan.
Nwoye knew that it was right to be masculine and to be violent, but somehow he still preferred the stories that his mother used to tell…
Ezinma took the dish in one hand and the empty water bowl in the other and went back to her mother's hut. “She should have been a boy,” Okonkwo said to himself again. His mind went back to Ikemefuna and he shivered.
“The world is large,” said Okonkwo. “I have even heard that in some tribes a man's children belong to his wife and her family.”
“That cannot be,” said Machi. “You might as well say that the woman lies on top of the man when they are making the children.”
It was a crime against the earth goddess to kill a clansman, and a man who committed it must flee from the land. The crime was of two kinds, male and female. Okonkwo had committed the female, because it had been inadvertent. He could return to the clan after seven years…
Living fire begets cold, impotent ash.