What is the distinction between "femboys" and "transgender?"

I see a lot of people call straight trans women gay men who larp and how is that different from being a femboy, if so? If I bound my chest, would I be a femboy? What's the line in the sand? Is "self-identification" really the deciding factor, because I'm wishy washy on that because it's influenced partially by how others perceive me. But even if others gender me female or are attracted to me, how is that different from a "trap" (same thing as femboy, just now considered politically incorrect)?