kid on the square

Dates back to the early 20th century. Later popularized by Mose Allison in his 1983 song "Kidding on the Square" on the album Middle Class White Boy (described in the liner notes as "joking with serious intent") and later by Al Franken describing the negative reaction of Paul Wolfowitz to one of his jokes in the 2003 book Lies and the Lying Liars Who Tell Them

kid on the square (third-person singular simple present kids on the square, present participle kidding on the square, simple past and past participle kidded on the square)

1. To be joking, but at the same time really mean it.
   • 1907, Alfred Damon Runyon, “The Defense of Strikerville”, in McClure's Magazine, volume 28, page 379:

     "I'm kiddin' on the square," said Hanks.

   • 1977, Dan Rather, Mickey Herskowitz, The Camera Never Blinks‎, →ISBN, page 66:

     So I always knew what Pierce meant, in a kidding-on-the-square kind of way.

   • 2006, Stuart Ostrow, Present at the Creation‎, →ISBN, page 46:

     "At least he likes historical characters," I kidded on the square. No one laughed so I went to work recruiting other directors.

• ha ha only serious