Answer
The term total depravity is really the first of five main points within what we would call Calvinistic theology, or Reformed theology. And the idea there is that, as a result of sin, mankind has become completely depraved. And that means in terms of breadth, from who we are to what we think to what we do, sin has affected each and every part of us. And so, that's what total depravity is: there's not a part of us that's inherently good. It's been misunderstood often by people thinking that total depravity is less of a sort of a breadth idea of sin affecting everything and more of a depth idea, that we are as sinful as we could possibly be, that nothing that we could ever do could be understood as anything other than just the pure bottom depths of depravity and sin. And that's not really what the concept of total depravity is meant to convey. Total depravity is meant to just say that there's not a single part of us that stands on its own as being worthwhile or good.