Odd words and phrases

I've noticed another couple of odd phrases and words recently. A newspaper article was about an accident that occurred in an "unmarked crosswalk." I couldn't help but wonder what that meant. I guess I've been under the impression that it was the markings that made a crosswalk. It's against the law to cross the street between intersections--unless there is a marked crosswalk. Is it okay to cross at any intersection? What exactly makes a marked crosswalk--lights? paint? If the paint is faded or the light is out, is it still a safe place to cross or is it now unmarked? I'm confused.

Another thing I read mentioned disinhibition. My first thought was, "huh?" I decided it must be the same as less inhibited or less inhibition. Does disinhibition sound that much more erudite? It surely caught my attention, but I'm not sure that's what the writer intended since I can't remember what in the heck the article was talking about. I guess I'm suffering from disremembrance.