how is masculinity defined in things fall apart? how does this definition shape the development of the characters? what might achebe be asserting about the igbo definition of masculinity? does the traditional definition of masculinity need to change? why

This is only a short answer space but I can give you a general answer. "Manliness" , to Okonkwo, is tied up with matters of physical power and prowess. The hiding of feelings is also an important part of it. Masculinity is one of Okonkwo's obsessions, and he defines masculinity quite narrowly. For him, any kind of tenderness is a sign of weakness and effeminacy. Male power lies in authority and brute force. But throughout the novel, we are shown men with more sophisticated understanding of masculinity. Okonkwo's harshness drives Nwoye away from the family and into the arms of the new religion.