too insulting, indecent, etc, to be said
say the unsayable to express an opinion thought to be too controversial to mention
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
How to use unsayable in a sentence
Kent herself has said the movie is about parenting, the unsayable extremes of what mothers can feel.
Talk, say the unsayable, bring his love in misty word lines before his eyes; look and forget a moment.Erik Dorn | Ben Hecht