“contumaciously”
Excellent!
Thirty years ago when I still read three newspapers a day Russell Baker wrote a piece entitled “In Praise of Ignorant Contumely,” which was very fine and very funny.
I carried around the faded newsprint copy for some years but eventually it was lost.
Even now in the near-deathless age of google I have been unable to dig it up again. But thanks for resurrecting the term, for me at least.
Remarkably, in its history the NYT has printed about a dozen articles with the words "contumely," "Russell" and "Baker." (And not all of them by Russell Baker.)
Here’s another one: