Svadharma is your own path. The Gītā says your own duty done imperfectly is better than someone else’s done well.
Going deeper
3.35 is a verse about not borrowing someone else's life. Your own duty, even done poorly, is better than another's done well. It is better to die in one's own duty, the verse adds, because another's duty is full of fear. The verse before, 3.34, warns that the senses have fixed likes and dislikes for their objects and that one should not fall under their sway, since they are enemies. Right after, in 3.36, Arjuna asks what pushes a person to do wrong even against their will. The story reads svadharma as your own path. In the Gītā the verse sits between a warning about the pull of the senses and a question about what drives people against their own will. See chapter 3 and what the Gītā says about dharma.