unassuageable

adj

1. (not-comparable, usually)Impossible to assuage

   “Haven't Americans lived long enough with the heartache of unassuageable grief?”

   “The most powerful character in the story, Diana, never truly appears, other than in radiant glimpses. The unassuageable anguish of the 12-year-old Harry’s loss gives Moehringer a potent, overarching literary device.”