Is There a Difference Between Understanding and Excusing?

It's a really difficult thing to try and figure out the difference between understanding some one and like forgiving them, or a o or excusing them. Is there a way to understand without excusing? Not a rhetorical question, genuine question that i don't know the answer to. It is really exhausting in practice, to have people make assumptions about you,. To have people see you as less than fully human. And it's really difficult to figure out a way through that when it's r of your daily life.