The use of words to convey a meaning that is the opposite of its literal meaning:
the irony of her reply, “How nice!” when I said I had to work all weekend.
I was looking through old emails yesterday when I came across an email from February from subscriber Sue P that I wasn’t aware had been received. Sorry Sue for not acknowledging and thanking you earlier. Sue’s email is headed IRONY ... explained in pictures and those pictures appear below, plus some more. I don't know if any have been photoshopped, I would like to believe that they haven't.