There's this weird thing going on with my copy of Inkscape. I'm trying to move some shape onto the outline of a character, but it won't stay where I put it. Instead it jumps onto a path that was previously drawn. A little thing shows up that says "smooth node To path" or "cusp node to path." And when I try to change the rotational axis of an object, I get the same problem. Is there some way to shut this specific function off?

Welcome to InkscapeForum!

That's called Snapping. Normally it's used to precisely place objects, but can also interfere with placement, if you don't intend to use it. There's a snap control bar which may either be across the top of the window, like the control bar for the other tools or command bar; or it may be along the right side of the window. Just unclick the 1st button and it will turn it all off.

Edit
It's possible that the control bar is hidden. And I'm not sure if it can be hidden without turning it off. But if you don't find it, click View menu > Snap, and then you'll see it.

Thank you very much.

You're welcome