unprintable

un- +‎ printable

unprintable (not comparable)

1. Not printable; obscene, or unable to be displayed textually.
   • 1912, Arthur Conan Doyle, The Lost World […], London, New York, N.Y.: Hodder and Stoughton, →OCLC:

     "There was poor old Wadley, of the Zoological Institute. Wadley sent a message: 'The President of the Zoological Institute presents his compliments to Professor Challenger, and would take it as a personal favor if he would do them the honor to come to their next meeting.' The answer was unprintable." "You don't say?" "Well, a bowdlerized version of it would run: 'Professor Challenger presents his compliments to the President of the Zoological Institute, and would take it as a personal favor if he would go to the devil.'"

   • 1949, Frank B. Gilbreth, Jr., Ernestine Gilbreth Carey, Cheaper by the Dozen:

     Once a neighbor complained that a Gilbreth had called the neighbor's boy a son of an unprintable word.

• printable

• printability

unprintable (plural unprintables)

1. Something that is not printable.
   • 2019, Richard Jennings, LabVIEW Graphical Programming, Fifth Edition, page 91:

     LabVIEW will interpret one- or two-character codes following the backslash character, as shown in Table 2.1. You can also enter unprintables by simply typing them into the string.