Acharya Prashant explains the concept of weakness as defined in the Bhagavad Gita, clarifying that it does not mean a lack of physical strength or the inability to complete a task. Instead, weakness is the failure to decide to do what is right despite knowing it is correct. He emphasizes that Shri Krishna teaches that success or failure in an action is irrelevant; what truly matters is the resolve to perform the right action without being paralyzed by the fear of consequences. This state of acting without concern for the outcome is known as selfless action. He illustrates this by praising a young child's courage to ask a question, contrasting it with the hesitation of older individuals who fear judgment or results.