Admittedly Off-Topic: The Word of the Day

I enjoy the discussions that I routinely have with my mother on “the word of the day” on dictionary.com.  Here’s what I wrote to her re: today’s word: “contradistinction,” meaning “distinction by opposition or contrast”:

The reason I don’t use “contradistinction” is that I regard it as redundant.  “Distinction” already implies the concept of “contrasted against.” 

I have a friend who uses the word “prewarn,” apparently unaware that “warn” means to give advanced notice of danger; one doesn’t warn someone of something that has already happened. Of course, there are people who admonish “be careful!” when someone has bumped his head, but that’s really idiotic.