From Longman Dictionary of Contemporary Englishunprintableun‧print‧a‧ble /ʌnˈprɪntəbəl/ adjective SWEARwords or remarks that are unprintable are so rude or shocking that you do not want to say what they are
Examples from the Corpus
unprintable• Chief McNally admits he's been called many things, some of them unprintable.• Most of what she said in the interview was unprintable.• Along the way they intend to write a book of their experiences, most of which will undoubtedly be totally unprintable.• But some dissenting comments made in private were unprintable. 